Category Archives: CMDB

June 16, 2010

CMDB in the Cloud: not your father’s CMDB

Bernd Harzog recently wrote a blog entry to examine whether “the CMDB [is] irrelevant in a Virtual and Cloud based world“. If I can paraphrase, his conclusion is that there will be something that looks like a CMDB but the current CMDB products are ill-equipped to fulfill that function. Here are the main reasons he gives for this prognostic:

  1. A whole new class of data gets created by the virtualization platform – specifically how the virtualization platform itself is configured in support of the guests and the applications that run on the guest.
  2. A whole new set of relationships between the elements in this data get created – specifically new relationships between hosts, hypervisors, guests, virtual networks and virtual storage get created that existing CMDB’s were not built to handle.
  3. New information gets created at a very rapid rate. Hundreds of new guests can get provisioned in time periods much too short to allow for the traditional Extract, Transform and Load processes that feed CMDB’s to be able to keep up.
  4. The environment can change at a rate that existing CMDB’s cannot keep up with. Something as simple as vMotion events can create thousands of configuration changes in a few minutes, something that the entire CMDB architecture is simply not designed to keep up with.
  5. Having portions of IT assets running in a public cloud introduces significant data collection challenges. Leading edge APM vendors like New Relic and AppDynamics have produced APM products that allow these products to collect the data that they need in a cloud friendly way. However, we are still a long way away from having a generic ability to collect the configuration data underlying a cloud based IT infrastructure – notwithstanding the fact that many current cloud vendors would not make this data available to their customers in the first place.
  6. The scope of the CMDB needs to expand beyond just asset and configuration data and incorporate Infrastructure Performance, Applications Performance and Service assurance information in order to be relevant in the virtualization and cloud based worlds.

I wanted to expand on some of these points.

New model elements for Cloud (bullets #1 and #2)

These first bullets are not the killers. Sure, the current CMDBs were designed before the rise of virtualized environment, but they are usually built on a solid modeling foundation that can easily be extend with new resources classes. I don’t think that extending the model to describe VM, VNets, Volumes, hypervisors and their relationships to the physical infrastructure is the real challenge.

New approach to “discovery” (bullets #3 and #4)

This, on the other hand is much more of a “dinosaurs meet meteorite” kind of historical event. A large part of the value provided by current CMDBs is their ability to automate resource discovery. This is often achieved via polling/scanning (at the hardware level) and heuristics/templates (directory names, port numbers, packet inspection, bird entrails…) for application discovery. It’s imprecise but often good enough in static environments (and when it fails, the CMDB complements the automatic discovery with a reconciliation process to let the admin clean things up). And it used to be all you could get anyway so there wasn’t much point complaining about the limitations. The crown jewel of many of today’s big CMDBs can often be traced back to smart start-ups specialized in application discovery/mapping, like Appilog (now HP, by way of Mercury) and nLayers (now EMC). And more recently the purchase of Tideway by BMC (ironically – but unsurprisingly – often cast in Cloud terms).

But this is not going to cut it in “the Cloud” (by which I really mean in a highly automated IT environment). As Bernd Harzog explains, the rate of change can completely overwhelm such discovery heuristics (plus, some of the network scans they sometimes use will get you in trouble in public clouds). And more importantly, there now is a better way. Why discover when you can ask? If resources are created via API calls, there are also API calls to find out which resources exist and how they are configured. This goes beyond the resources accessible via IaaS APIs, like what VMWare, EC2 and OVM let you retrieve. This “don’t guess, ask” approach to discovery needs to also apply at the application level. Rather than guessing what software is installed via packet inspection or filesystem spelunking, we need application-aware discovery that retrieves the application and configuration and dependencies from the application itself (or its underlying framework). And builds a model in which the connections between application entities are expressed in terms of the configuration settings that drive them rather than the side effects by which they can be noticed.

If I can borrow the words of Lew Cirne:

“All solutions built in the pre-cloud era are modeled on jvms (or their equivalent), hosts and ports, rather than the logical application running in a more fluid environment. If the solution identifies a web application by host/port or some other infrastructural id, then you cannot effectively manage it in a cloud environment, since the app will move and grow, and your management system (that is, everything offered by the Big 4, as well as all infrastructure management companies that pay lip service to the application) will provide nearly-useless visibility and extraordinarily high TCO.”

I don’t agree with everything in Lew Cirne’s post, but this diagnostic is correct and well worded. He later adds:

“So application management becomes the strategic center or gravity for the client of a public or private cloud, and infrastructure-centric tools (even ones that claim to be cloudy) take on a lesser role.”

Which is also very true even if counter-intuitive for those who think that

cloud = virtualization (in the “fake machine” interpretation of virtualization)

Embracing such a VM-centric view naturally raises the profile of infrastructure management compared to application management, which is a fallacy in Cloud computing.

Drawing the line between Cloud infrastructure management and application management (bullet #5)

This is another key change that traditional CMDBs are going to have a hard time with. In a Big-4 CMDB, you’re after the mythical “single source of truth”. Even in a federated CMDB (which doesn’t really exist anyway), you’re trying to have a unified logical (if not physical) repository of information. There is an assumption that you want to manage everything from one place, so you can see all the inter-dependencies, across all layers of the stack (even if individual users may have a scope that is limited by permissions). Not so with public Clouds and even, I would argue, any private Cloud that is more than just a “cloud” sticker slapped on an old infrastructure. The fact that there is a clean line between the infrastructure model and the application model is not a limitation. It is empowering. Even if your Cloud provider was willing to expose a detailed view of the underlying infrastructure you should resist the temptation to accept. Despite the fact that it might be handy in the short term and provide an interesting perspective, it is self-defeating in the long term from the perspective of realizing the productivity improvements promised by the Cloud. These improvements require that the infrastructure administrator be freed from application-specific issues and focus on meeting the contract of the platform. And that the application administrator be freed from infrastructure-level concerns (while at the same time being empowered to diagnose application-level concerns). This doesn’t mean that the application and infrastructure models should be disconnected. There is a contract and both models (infrastructure and consumption) should represent it in the same way. It draws a line, albeit one with some width.

Blurring the line between configuration and monitoring (bullet #6)

This is another shortcoming of current CMDBs, but one that I think is more easily addressed. The “contract” between the Cloud infrastructure and the consuming application materializes itself in a mix of configuration settings, administrative capabilities and monitoring data. This contract is not just represented by the configuration-centric Cloud API that immediately comes to mind. It also includes the management capabilities and monitoring points of the resulting instances/runtimes.

Wither CMDB?

Whether all these considerations mean that traditional CMDBs are doomed in the Cloud as Bernd Harzog posits, I don’t know. In this post, BMC’s Kia Behnia acknowledges the importance of application management, though it’s not clear that he agrees with their primacy. I am also waiting to see whether the application management portfolio he has assembled can really maps to the new methods of application discovery and management.

But these are resourceful organization, with plenty of smart people (as I can testify: in the end of my HP tenure I worked with the very sharp CMDB team that came from the Mercury acquisition). And let’s keep in mind that customers also value the continuity of support of their environment. Most of them will be dealing with a mix of old-style and Cloud applications and they’ll be looking for a unified management approach. This helps CMDB incumbents. If you doubt the power to continuity, take a minute to realize that the entire value proposition of hypervisor-style virtualization is centered around it. It’s the value of backward-compatibility versus forward-compatibility. in addition, CMDBs are evolving into CMS and are a lot more than configuration repositories. They are an important supporting tool for IT management processes. Whether, and how, these processes apply to “the Cloud” is a topic for another post. In the meantime, read what the IT Skeptic and Rodrigo Flores have to say.

I wouldn’t be so quick to count the Big-4 out, even though I work every day towards that goal, building Oracle’s application and middleware management capabilities in conjunction with my colleagues focused on infrastructure management.

If the topic of application-centric management in the age of Cloud is of interest to you (and it must be if you’ve read this long entry all the way to the end), You might also find this previous entry relevant: “Generalizing the Cloud vs. SOA Governance debate“.

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Filed under Application Mgmt, Automation, Cloud Computing, CMDB, CMDB Federation, Everything, IT Systems Mgmt, ITIL, Mgmt integration, Middleware, Utility computing, Virtualization

April 2, 2010

Enterprise application integration patterns for IT management: a blast from the past or from the future?

In a recent blog post, Don Ferguson (CTO at CA) describes CA Catalyst, a major architectural overhaul which “applies enterprise application integration patterns to the problem of integrating IT management systems”. Reading this was fascinating to me. Not because the content was some kind of revelation, but exactly for the opposite reason. Because it is so familiar.

For the better part of the last decade, I tried to build just this at HP. In the process, I worked with (and sometimes against) Don’s colleague at IBM, who were on the same mission. Both companies wanted a flexible and reliable integration platform for all aspects of IT management. We had decided to use Web services and SOA to achieve it. The Web services management protocols that I worked on (WSMF, WSDM, WS-Management and the “reconciliation stack”) were meant for this. We were after management integration more than manageability. Then came CMDBf, another piece of the puzzle. From what I could tell, the focus on SOA and Web services had made Don (who was then Mr. WebSphere) the spiritual father of this effort at IBM, even though he wasn’t at the time focused on IT management.

As far as I know, neither IBM nor HP got there. I covered some of the reasons in this post-mortem. The standards bickering. The focus on protocols rather than models. The confusion between the CMDB as a tool for process/service management versus a tool for software integration. Within HP, the turmoil from the many software acquisitions didn’t help, and there were other reasons. I am not sure at this point whether either company is still aiming for this vision or if they are taking a different approach.

But apparently CA is still on this path, and got somewhere. At least according to Don’s post. I have no insight into what was built beyond what’s in the post. I am not endorsing CA Catalyst, just agreeing with the design goals listed by Don. If indeed they have built it, and the integration framework resists the test of time, that’s impressive. And exciting. It apparently even uses some the same pieces we were planning to use, namely WS-Management and CMDBf (I am reluctantly associated with the first and proudly with the second).

While most readers might not share my historical connection with this work, this is still relevant and important to anyone who cares about IT management in the enterprise. If you’re planning to be at CA World, go listen to Don. Web services may have a bad name, but the technical problems of IT management integration remain. There are only a few routes to IT management automation (I count seven, the one taken by CA is #2). You can throw away SOAP if you want, you still need to deal with protocol compatibility, model alignment and instance reconciliation. You need to centralize or orchestrate the management operations performed. You need to be able to integrate with complementary products or at the very least to effectively incorporate your acquisitions. It’s hard stuff.

Bonus point to Don for not forcing a “Cloud” angle for extra sparkle. This is core IT management.

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Filed under Automation, CA, CMDB, CMDB Federation, CMDBf, Everything, IT Systems Mgmt, Mgmt integration, Modeling, People, Protocols, SOAP, Specs, Standards, Tech, Web services, WS-Management

March 1, 2010

Two versions of a protocol is one too many

There is always a temptation, when facing a hard design decision in the process of creating an interface or a protocol, to produce two (or more) versions. It’s sometimes a good idea, as a way to explore where each one takes you so you can make a more informed choice. But we know how this invariably ends up. Documents get published that arguably should not. It’s even harder in a standard working group, where someone was asked (or at least encouraged) by the group to create each of the alternative specifications. Canning one is at best socially awkward (despite the appearances, not everyone in standards is a psychopath or a sadist) and often politically impossible.

And yet, it has to be done. Compare the alternatives, then pick one and commit. Don’t confuse being accommodating with being weak.

The typical example these days is of course SOAP versus REST: the temptation is to support both rather than make a choice. This applies to standards and to proprietary interfaces. When a standard does this, it hurts rather than promote interoperability. Vendors have a bit more of an excuse when they offer a choice (“the customer is always right”) but in reality it forces customers to play Russian roulette whether they want it or not. Because one of the alternatives will eventually be left behind (either discarded or maintained but not improved). If you balance the small immediate customer benefit of using the interface style they are most used to with the risk of redoing the integration down the road, the value proposition of offering several options crumbles.

[Pedantic disclaimer: I use the term “REST” in this post the way it is often (incorrectly) used, to mean pretty much anything that uses HTTP without a SOAP wrapper. The technical issues are a topic for other posts.]

CMDBf

CMDBf v1 is a DMTF standard. It is a SOAP-based protocol. For v2, it has been suggested that there should a REST version. I don’t know what the CMDBf group (in which I participate) will end up doing but I’ve made my position clear: I could go either way (remain with SOAP or dump it) but I do not want to have two versions of the protocol (one SOAP one REST). If we think we’re better off with a REST version, then let’s make v2 REST-only. Supporting both mechanisms in v2 would be stupid. They would address the same use cases and only serve to provide political ass-coverage. There is no functional need for both. The argument that we need to keep supporting SOAP for the benefit of those who implemented v1 doesn’t fly. As an implementer, nobody is saying that you need to turn off your v1 services the second you launch the v2 version.

DMTF Cloud

Between the specifications submitted directly to DMTF, the specifications developed by DMTF “partner” organizations and the existing DMTF protocols, the DMTF Cloud effort is presented with a mix of SOAP, RESTful and XML-RPC-over-HTTP options. In the process of deciding what to create or adopt I am sure that the temptation will be high to take the easy route of supporting several versions to placate everyone. But such a “consensus” would be achieved on the back of the implementers so I very much hope it won’t be the case.

When it is appropriate

There are cases where supporting alternatives options is worth the cost. But it typically happens when they serve very different use cases. Think of SAX versus DOM, which have clearly differentiated sweetspots. In the Cloud world, Amazon S3 gives us interesting examples of both justified and extraneous alternatives. The extraneous one is the choice between REST and SOAP for the S3 API. I often praise AWS for its innovation and pragmatism, but this is an example of something that only looks pragmatic. On the other hand, the AWS import/export mechanism is a useful alternative. It allows you to physically ship a device with a few terabytes of data to Amazon. This is technically an alternative to the S3 programmatic interface, but one with obviously differentiated use cases. I recommend you reserve the use of “alternative APIs” for such scenarios.

If it didn’t work for Tiger Woods, it won’t work for your Cloud API either. Learn to commit.

[CLARIFICATION: based on some of the early Twitter feedback on this entry, I want to clarify that it’s alternative versions that I am against, not successive versions (i.e. an evolution of the interface over time). How to manage successive versions properly is a whole other debate.]

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Filed under Amazon, API, Cloud Computing, CMDB, CMDBf, DMTF, Everything, IT Systems Mgmt, Protocols, REST, SOAP, Specs, Standards, Utility computing, Web services

January 20, 2010

Generalizing the Cloud vs. SOA Governance debate

There have been some interesting discussions recently about the relationship between Cloud management and SOA management/governance (run-time and design-time). My only regret is that they are a bit too focused on determining winners and loosers rather than defining what victory looks like (a bit like arguing whether the smartphone is the triumph of the phone over the computer or of the computer over the phone instead of discussing what makes a good smartphone).

To define victory, we need to answer this seemingly simple question: in what ways is the relationship between a VM and its hypervisor different from the relationship between two communicating applications?

More generally, there are three broad categories of relationships between the “active” elements of an IT system (by “active” I am excluding configuration, organization, management and security artifacts, like patch, department, ticket and user, respectively, to concentrate instead on the elements that are on the invocation path at runtime). We need to understand if/how/why these categories differ in how we manage them:

  • Deployment relationships: a machine (or VM) in a physical host (or hypervisor), a JEE application in an application server, a business process in a process engine, etc…
  • Infrastructure dependency relationships (other than containment): from an application to the DB that persists its data, from an application tier to web server that fronts it, from a batch job to the scheduler that launches it, etc…
  • Application dependency relationships: from an application to a web service it invokes, from a mash-up to an Atom feed it pulls, from a portal to a remote portlet, etc…

In the old days, the lines between these categories seemed pretty clear and we rarely even thought of them in the same terms. They were created and managed in different ways, by different people, at different times. Some were established as part of a process, others in a more ad-hoc way. Some took place by walking around with a CD, others via a console, others via a centralized repository. Some of these relationships were inventoried in spreadsheets, others on white boards, some in CMDBs, others just in code and in someone’s head. Some involved senior IT staff, others were up to developers and others were left to whoever was manning the controls when stuff broke.

It was a bit like the relationships you have with the taxi that takes you to the airport, the TSA agent who scans you and the pilot who flies you to your destination. You know they are all involved in your travel, but they are very distinct in how you experience and approach them.

It all changes with the Cloud (used as a short hand for virtualization, management automation, on-demand provisioning, 3rd-party hosting, metered usage, etc…). The advent of the hypervisor is the most obvious source of change: relationships that were mostly static become dynamic; also, where you used to manage just the parts (the host and the OS, often even mixed as one), you now manage not just the parts but the relationship between them (the deployment of a VM in a hypervisor). But it’s not just hypervisors. It’s frameworks, APIs, models, protocols, tools. Put them all together and you realize that:

  • the IT resources involved in all three categories of relationships can all be thought of as services being consumed (an “X86+ethernet emulation” service exposed by the hypervisor, a “JEE-compatible platform” service exposed by the application server, an “RDB service” expose by the database, a Web services exposed via SOAP or XML/JSON over HTTP, etc…),
  • they can also be set up as services, by simply sending a request to the API of the service provider,
  • not only can they be set up as services, they are also invoked as such, via well-documented (and often standard) interfaces,
  • they can also all be managed in a similar service-centric way, via performance metrics, SLAs, policies, etc,
  • your orchestration code may have to deal with all three categories, (e.g. an application slowdown might be addressed either by modifying its application dependencies, reconfiguring its infrastructure or initiating a new deployment),
  • the relationships in all these categories now have the potential to cross organization boundaries and involve external providers, possibly with usage-based billing,
  • as a result of all this, your IT automation system really needs a simple, consistent, standard way to handle all these relationships. Automation works best when you’ve simplified and standardize the environment to which it is applied.

If you’re a SOA person, your mental model for this is SOA++ and you pull out your SOA management and governance (config and runtime) tools. If you are in the WS-* obedience of SOA, you go back to WS-Management, try to see what it would take to slap a WSDL on a hypervisor and start dreaming of OVF over MTOM/XOP. If you’re into middleware modeling you might start to have visions of SCA models that extend all the way down to the hardware, or at least of getting SCA and OSGi to ally and conquer the world. If you’re a CMDB person, you may tell yourself that now is the time for the CMDB to do what you’ve been pretending it was doing all along and actually extend all the way into the application. Then you may have that “single source of truth” on which the automation code can reliably work. Or if you see the world through the “Cloud API” goggles, then this “consistent and standard” way to manage relationships at all three layers looks like what your Cloud API of choice will eventually do, as it grows from IaaS to PaaS and SaaS.

Your background may shape your reference model for this unified service-centric approach to IT management, but the bottom line is that we’d all like a nice, clear conceptual model to bridge and unify Cloud (provisioning and containment), application configuration and SOA relationships. A model in which we have services/containers with well-defined operational contracts (and on-demand provisioning interfaces). Consumers/components with well-defined requirements. APIs to connect the two, with predictable results (both in functional and non-functional terms). Policies and SLAs to fine-tune the quality of service. A management framework that monitors these policies and SLAs. A common security infrastructure that gets out of the way. A metering/billing framework that spans all these interactions. All this while keeping out of sight all the resource-specific work needed behind the scene, so that the automation code can look as Zen as a Japanese garden.

It doesn’t mean that there won’t be separations, roles, processes. We may still want to partition the IT management tasks, but we should first have a chance to rejigger what’s in each category. It might, for example, make sense to handle provider relationships in a consistent way whether they are “deployment relationships” (e.g. EC2 or your private IaaS Cloud) or “application dependency relationships” (e.g. SOA, internal or external). On the other hand, some of the relationships currently lumped in the “infrastructure dependency relationships” category because they are “config files stuff” may find different homes depending on whether they remain low-level and resource-specific or they are absorbed in a higher-level platform contract. Any fracture in the management of this overall IT infrastructure should be voluntary, based on legal, financial or human requirements. And not based on protocol, model, security and tool disconnect, on legacy approaches, on myopic metering, that we later rationalize as “the way we’d want things to be anyway because that’s what we are used to”.

In the application configuration management universe, there is a planetary collision scheduled between the hypervisor-centric view of the world (where virtual disk formats wrap themselves in OVF, then something like OVA to address, at least at launch time, application and infrastructure dependency relationships) and the application-model view of the world (SOA, SCA, Microsoft Oslo at least as it was initially defined, various application frameworks…). Microsoft Azure will have an answer, VMWare/Springsouce will have one, Oracle will too (though I can’t talk about it), Amazon might (especially as it keeps adding to its PaaS portfolio) or it might let its ecosystem sort it out, IBM probably has Rational, WebSphere and Tivoli distinguished engineers locked into a room, discussing and over-engineering it at this very minute, etc.

There is a lot at stake, and it would be nice if this was driven (industry-wide or at least within each of the contenders) by a clear understanding of what we are aiming for rather than a race to cobble together partial solutions based on existing control points and products (e.g. the hypervisor-centric party).

[UPDATED 2010/1/25: For an illustration of my statement that “if you’re a SOA person, your mental model for this is SOA++”, see Joe McKendrick’s “SOA’s Seven Greatest Mysteries Unveiled” (bullet #6: “When you get right down to it, cloud is the acquisition or provisioning of reusable services that cross enterprise walls. (…)  They are service oriented architecture, and they rely on SOA-based principles to function.”)]

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Filed under Application Mgmt, Automation, Cloud Computing, CMDB, Everything, Governance, IT Systems Mgmt, ITIL, Mgmt integration, Middleware, Modeling, OSGi, SCA, Utility computing, Virtualization, WS-Management

September 24, 2009

The future (2006 version), has arrived

Remember 2006? Things were starting to fall into place for IT management integration and automation:

  • SDD was already on its way to cleanly describe/package/manage the lifecycle of simple and composite applications alike,
  • the first version of SML came out to capture all the relevant constraints of complex and composite systems and open the door to “desired-state management”,
  • the CMDBf effort was started to seamlessly integrate all sources of configuration and provide a bird-eye view of your entire IT infrastructure, and
  • the WSDM/WS-Management convergence/reconciliation was announced and promised to free management consoles from supporting many resource discovery, collection and control mechanisms and from having platform/library dependencies between the manager and its targets.

It looked like we were a year or two from standardization on all these and another year or two from shipping implementations. Things were looking good.

Good news: the schedule was respected. SDD, SML and CMDBf are now all standards (at OASIS, W3C and DMTF respectively). And today the Eclipse COSMOS project announced the release of COSMOS 1.1 which implements them all. The WSDM/WS-Management convergence is the only one that didn’t quite go according to the plan but it is about to come out as a standard too (in a pared-down form).

Bad news: nobody cares. We’ve moved on to “private clouds”.

Having been involved with these specifications in various degrees (a little bit on SDD, a fair amount on SML and a lot on CMDBf and WSDM/WS-Management) I am not as detached as my sarcastic tone may suggest. But as they say in action movies, “don’t let sentiments get in the way of the mission”.

There is still a chance to reuse parts of this stack (e.g. the CMDBf query language) and there are lessons to learn from our errors. The over-promising, the technical misjudgments, the political bickering, the lack of concrete customer validation, etc. To some extent this work was also victim of collateral damages from the excesses of WS-* (I am looking at you WS-Addressing). We also failed to notice the rise of the hypervisor in our peripheral vision.

I tried to capture some important lessons in this post-mortem. For the edification of the cloud generation. I also see a pendulum in action. Where we over-engineered I now see some under-engineering (overly granular interaction models, overemphasis on the virtual machine as the unit of everything, simplistic constraint models, underestimation of config/patching issues…). Things will come around and may eventually look familiar (suggested exercise: compare PubSubHubBub with WS-Notification).

As long as each iteration gets us closer to the goal things are good.

See you in 2012. Same place, same day, same time.

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Filed under Application Mgmt, Automation, Cloud Computing, CMDB, CMDB Federation, CMDBf, Desired State, Everything, IT Systems Mgmt, Manageability, Mgmt integration, Modeling, Protocols, SML, Specs, Standards, Utility computing, WS-Management

July 28, 2009

REST in practice for IT and Cloud management (part 2: configuration management)

What benefits does REST provide for configuration management (in traditional data centers and in Clouds)?

Part 1 of the “REST in practice for IT and Cloud management” investigation looked at Cloud APIs from leading IaaS providers. It examined how RESTful they are and what concrete benefits derive from their RESTfulness. In part 2 we will now look at the configuration management domain. Even though it’s less trendy, it is just as useful, if not more, in understanding the practical value of REST for IT management. Plus, as long as Cloud deployments are mainly of the IaaS kind, you are still left with the problem of managing the configuration of everything that runs of top the virtual machines (OS, middleware, DB, applications…). Or, if you are a glass-half-full person, here is another way to look at it: the great thing about IaaS (and host virtualization in general) is that you can choose to keep your existing infrastructure, applications and management tools (including configuration management) largely unchanged.

At first blush, REST is ideally suited to configuration management.

The RESTful Cloud APIs have no problem retrieving resource descriptions, but they seem somewhat hesitant in the way they deal with resource-specific actions. Tim Bray described one of the challenges in his well-considered Slow REST post. And indeed, applying REST to these “do something that may take some time and not result exactly in what was requested” scenarios is a lot less straightforward than when you’re just doing document/data retrieval. In contrast you’d think that applying REST to the task of retrieving configuration data from a CMDB or other configuration store would be a no-brainer. Especially in the IT management world, where we already have explicit resource models and a rich set of relationships defined. Let’s give each resource a URI that responds to HTTP GET requests, let’s turn the associations into hyperlinks in the resource presentation, let’s mint a MIME type to represent this format and we are out of the office in time for a 4:00PM tennis game when all the courts are available (hopefully our tennis partners are as bright as us and can get out early too). This “work smarter not harder” approach would allow us to present this list of benefits in our weekly progress report:

-1- A URI-based scheme makes the protocol independent of the resource topology, unlike today’s data stores that usually struggle to represent relationships between stores.

-2- It is simpler to code against than CIM-over-HTTP or WS-Management. It is cross-platform, unlike WMI or JMX.

-3- It makes it trivial to browse the configuration data from a Web browser (the resources themselves could provide an HTML representation based on content-type negotiation, or a simple transformation could generate it for the Web browser).

-4- You get REST-induced caching and scalability.

In the shower after the tennis game, it becomes apparent that benefit #4 is largely irrelevant for IT management use cases. That the browser in #3 would not be all that useful beyond simple use cases. That #2 is good for karma but developers will demand a library that hides this benefit anyway. And that the boss is going to say that he doesn’t care about #1either because his product is “the single source of truth” so it needs to import from the other configuration store, not reference them.

Even if we ignore the boss (once again) it only  leaves #1 as a practical benefit. Surprise, that’s also the aspect that came out on top of the analysis in part 1 (see “the API doesn’t constrain the design of the URI space” highlight, reinforced by Mark’s excellent comment on the role of hypertext). Clearly, there is something useful for IT management in this “hypermedia” thing. This will largely be the topic of part 3.

There are also quite a few things that this RESTification of the configuration management store doesn’t solve:

-1- The ability to query: “show me all the WebLogic instances that run on a Windows host and don’t have patch xyz applied”. You don’t have much of a CMDB if you can’t answer this. For an analogy, remember (or imagine) a pre-1995 Web with no search engine, where you can only navigate by starting from your browser home page and clicking through static links step by step, or through bookmarks.

-2- The ability to retrieve the configuration change history and to compare configurations across resources (or to a reference configuration).

This is not to say that these two features cannot be built on top of a RESTful IT resource model. Just that they are the real meat of configuration management (rather than a simple resource-by-resource configuration browser) and that your brilliant re-architecture hasn’t really helped in addressing them. Does a RESTful foundation make these features harder to build? Not necessarily, but there are some tricky aspects to take care of:

-1- In hypermedia systems, the links are usually part of the resource representation, not resources of their own. In IT management, relationships/associations can have their own lifecycle and configuration properties.

-2- Be careful that you can really maintain the address of a resource. It’s one thing to make sure that a UUID gets maintained as a resource configuration changes, it’s another to ensure that a dereferenceable URI remains unchanged. For example, the admin server of a cluster may move over time from one node to another.

More fundamentally, the ability to deal with multiple resources at the same time and/or to use the model at different levels of granularity is often a challenge. Either you make your protocol more complex to account for this or your pollute your resource model (with a bunch of arbitrary “groups”, implicit or explicit).

We saw this in the Cloud APIs too. It typically goes something like this: you can address an individual server (called “foo”) by sending requests to http://Cloudprovider.com/server/foo. Drop the “foo” part of the URL and now you can address all the servers, for example to retrieve their configuration or possibly to reboot them. This gives me a way of dealing with multiple resources at time, but only along the lines pre-defined by the API. What if I want to deal only with the servers that host nodes of a given cluster. Sorry, not possible. What if the servers have different hosts in their URIs (remember, “the API doesn’t constrain the design of the URI space”)? Oops.

WS-Management, in the SOAP world, takes this one step further with Selectors, through which you can embed some kind of query, the result of which is what you are addressing in your message. Or, if all you want to do is GET, you can model you entire datacenter as one giant virtual XML doc (a document which is never assembled in practice) and use WSRF/WSDM’s “QueryExpression” or WS-Management’s “FragmentTransfer” to the same effect. BTW, I have issues with the details of how these mechanisms work (and I have described an alternative under the motto “if you are going to suffer with WS-Addressing, at least get some value out of it”).

These are all non-RESTful atrocities to a RESTafarian, but in my mind the Cloud REST API reviewed in part 1 have open Pandora’s box by allowing less-qualified URIs to address all instances of a class. I expect you’ll soon see more precise query parameters in these URIs and they’ll look a lot like WS-Management Selectors (e.g. http://Cloudprovider.com/server?OS=Linux&CPUType=X86). Want to take bets about when a Cloud API URI format with an embedded regex first arrives?

When you need this, my gut feeling is that you are better off not worrying too much about trying to look RESTful. There is no shame to using an RPC pattern in the right circumstances. Don’t be the stupid skier who ends up crashing in a tree because he is just too cool for the using snowplow position.

One of the most common reasons to deal with multiple resources together is to run queries such as the “show me all the WebLogic instances that run on a Windows host and don’t have patch xyz applied” example above. Such a query mechanism recently became a DMTF standard, it’s called CMDBf. It is SOAP-based and doesn’t attempt to have anything to do with REST. Not that it didn’t cross the mind of a bunch of people, lead by Michael Coté when CMDBf first emerged (read the comments too). But as James Governor rightly predicted in the first comment, Coté heard “dick” from us on this (I represented HP in CMDBf and ended up being an editor of the specification, focusing on the “query” part). I don’t remember reading the entry back then but I must have since I have been a long time Coté fan. I must have dismissed the idea so quickly that it didn’t even register with my memory. Well, it’s 2009 now, CMDBf v1 is a DMTF standard and guess what? I, and many other SOAP-the-world-till-it-shines alumni, are looking a lot more seriously into what’s in this REST thing (thus this series of posts for me). BTW in this piece Coté also correctly predicted that CMDBf would be “more about CMDB interoperation than federation” but that didn’t take as much foresight (it was pretty obvious to me from the start).

Frankly I am still not sure that there is much benefit from REST in what CMDBf does, which is mostly a query interface. Yes the CMDBf query and its response go over SOAP. Yes in this case SOAP is mostly a useless wrapper since none of the implementations will likely support any WS-* SOAP header (other than paying the WS-Addressing tax). Sure we could remove it and send plain XML over HTTP. Or replace the SOAP wrapper with an Atom wrapper. Would it be anymore RESTful? Not one bit.

And I don’t see how to make it more RESTful. There are plenty of things in the periphery the query operation that can be made RESTful, along the lines of what I described above. REST could make the discovery/reconciliation tasks of the CMDB more efficient. The CMDBf query result format could be improved so that from the returned elements I can navigate my way among resources by following hyperlinks. But the query operation itself looks fundamentally RPCish to me, just like my interaction with the Google search page is really an RPC call that happens to return a Web page full of hyperlinks. In a way, this query (whether Google or CMDBf) can at best be the transition point from RPC to REST. It can return results that open a world of RESTful requests to you, but the query invocation itself is not RESTful. And that’s OK.

In part 3 (now available), I will try to synthesize the lessons from the Cloud APIs (part 1) and configuration management (this post) and extract specific guidance to get the best of what REST has to offer in future IT management protocols. Just so you can plan ahead, in part 4 I will reform the US health care system and in part 5 I will provide a practical roadmap for global nuclear disarmament. Suggestions for part 6 are accepted.

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Filed under API, Application Mgmt, Automation, Cloud Computing, CMDB, CMDB Federation, CMDBf, DMTF, Everything, IT Systems Mgmt, Mashup, Mgmt integration, Modeling, REST, SOAP, SOAP header, Specs, Standards, Utility computing

July 6, 2009

The CMDBf specification is now a DMTF standard

The CMDBf specification has finished its trek through the DMTF standard process. The last step was board approval and finally here is the official DMTF standard. It’s called version 1.0.0 which is a bit confusing since the version submitted to DMTF was dubbed “version 1.0”. I guess it means that this standard is the first version of the DMTF specification called CMDBf.

If you have been following the process closely, then you won’t find many technical changes since the last public draft. If you last read the specification when it was submitted to DMTF, then you’ll notice several improvements but no drastic change. If you are yet to take a first look at CMDBf, now is the perfect time.

To help you in that endeavor, I plan to update the query pseudo-algorithm to conform to the standard version of the specification when I get a chance. In the meantime, the slightly-outdated one is probably still helpful in wrapping your mind around the query mechanism.

Gentle(wo)men, rev your (query) engines.

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Filed under CMDB, CMDB Federation, CMDBf, DMTF, Everything, IT Systems Mgmt, Specs, Standards

April 7, 2009

“Federationing”

I am glad to see that, as it inches towards standardization in the DMTF, the CMDBf specification is getting more visibility. Forrester’s Glenn O’Donnell recently wrote very positively about it on his blog, presenting it as a key enabler for a federation of MDRs (Management Data Repositories, a term introduced by the CMDBf specification so don’t look for it in ITIL). He argues this is the only way (rather than a single data store) to fulfill the ITIL-defined role of a CMS. Rob England (the IT Skeptic) has also shared his thoughts about CMDBf and they were noticeably less enthusiastic, to say the least. While Glenn calls the specification “profound”, Rob calls it “the most over-hyped vendor marketing smokescreen ever”. There is plenty of room in between them, which is where I sit. As I explained before, it does have real value (as a query language/protocol for system integration) but is nowhere near providing “federation” capabilities.

I am happy to see Glenn approve of CMDBf and I agree with him that accurate specialized MDRs are more useful than a single store that attempts to capture all the relevant data. As Glenn puts it, “pockets of the truth are far superior to unified ambiguity”. But I wasn’t very comfortable with the tone of his article, which seemed to almost encourage the proliferation of these MDRs. Maybe he was just trying to present a clean break with the “one big CMDB” approach and overreached. Or maybe I am just not reading properly.

Because while I agree that the answer is not “one and only one store” I also don’t want to loose the value of having as much unification of the IT model as possible. Both at the data level (i.e. same metamodel/model, consistent retention/roll-up policies…) and the access level (i.e. in the same physical store, with shared access control, accessible using a well-known DSL for data manipulation…). Metamodel transformation and model bridging are costly (in accuracy, maintenance, reliability). If your CMS does more than just support a  “model navigation” GUI it may then need to run large queries that go across several portions of your IT model, including multiple different domains (e.g. a compliance rule kicked-off at the app level based on the type of data it manipulates that ends up having to look at the physical location of the servers running the hypervisors for the virtual machines that power the app). Through such global queries you can apply configuration rules, do impact analysis, event correlation, provide context to your transaction tracing, etc. No consolidation means no such queries (or a very limited subset). Considering the current state of federation, there is a lot more that you can do with your CMS if you have a very small number of MDRs rather than a sea of “federated” MDRs. This is why, as Oracle acquires IT management companies, we deliberately integrate their repositories with Enterprise Manager.

[UPDATED 2009/4/8: More, along the same line, from Glenn and his co-author Carlos Casanova available here. And my CMDBf partner-in-crime Van Wiles also responded to Glenn, bringing a BMC perspective.]

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Filed under Application Mgmt, Automation, CMDB, CMDB Federation, CMDBf, Everything, IT Systems Mgmt, ITIL, Mgmt integration, Modeling, Query, Specs, Standards

March 2, 2009

CMDBf is a lot more and a lot less than you think

The DMTF CMDBf working group has recently published an updated draft of its specification. The final version should follow soon and I don’t expect major changes so now is not a bad time to start thinking about what this baby can do.

Since CMDBf stands for “configuration management database federation”, you might think the obvious answer to the “what can it do” question is “build a federation of configuration management databases”. Except it’s not. Despite its name, CMDBf provides little support for federation unless you take a very loose definition of the term. The specification gives you a query language and a very simple registration interface, with a sprinkle of metadata to improve interoperability. The query language lets you talk to a CMDB to retrieve information on configuration items (CIs) that it knows about. The registration interface lets you keep a CMDB informed of changes to CIs that it may care about. If you want to build on top of this a real federation, one that scales to the type of environment that CMDBs are used for today, you have to go further than what the specification provides. What CMDBf does give you is some amount of integration between CMDBs (at the protocol level at least, not at the model level). It may not sound like much but it is a lot of progress on the current situation and the right incremental step, whether you are aiming for true federation as the end goal or not.

That’s the “a lot less than you think” part. So, what’s the “a lot more than you think” part? Good stuff all around:

CMDBf provides a metamodel that is well-suited for complex IT systems and it provides an elegant graph-oriented query language on top of it. The most convenient representation for an IT system is neither “one big XML document” nor “a sea of nodes and edges”. CMDBf gives you a middle ground: a graph model with XML leaf nodes. So you can precisely model the relationships between your IT elements using explicit relationships (with their own records), but you can also attach a well-understood piece of XML to an item as a record without having to break that XML into a bunch of tiny relationships.

I am pretty sure there are other domains, beyond IT systems, for which this would be useful. It will be interesting to see if the CMDBf specification gets considered outside of its intended scope. But these domains are more likely to end up using RDF/OWL/SPARQL instead. Not everyone has made the leap from XML as a tool to XML as a religion, which made CMDBf necessary for us. But let’s not veer into another rant.

Let’s go back instead to describing how useful CDMBf can be to IT systems management, independently of any “federation” objective. Let me put it this way: if one was to create from scratch a configuration store for IT systems they should strongly consider the CMDBf conceptual model as the base metamodel. And something along the lines of the CMDBf Query (though not necessarily through its XML serialization) as the native query language for it. Most CMDBf implementers of course are not in this situation. Rather than writing the store from scratch they will create a CMDBf wrapper/interface on their current CMDB. And that’s fine too. CMDBf will work well as an interoperability protocol. Putting aside my gripes about XPath overuse, CMDBf strikes a reasonable balance that makes it implementable on top of any back-end technology (relational, XML, RDF, in-memory objects, bags of name-value pairs…). And the query patterns it supports map well to CMDB-to-CMDB integration use cases. But it is underselling it, in my view, to restrict it to this over-the-wire interoperability scenario. CMDBf also provides a very useful foundation for local access to the CMDB. CMDBf graph queries can support powerful visualization of the content of the CMDB. They can support the definition of configuration rules. They can support in-depth inspection of relationships (e.g. fault tree).

And that may jsut be the beginning. It could take three directions after v1:

The first one, as always for a standard, is that it is ignored and becomes irrelevant. I have to reluctantly list this one first, because it is statistically the most likely for a new standard. Especially one that is not a ratification of an existing de facto standard. And one that threatens an important control point for vendors. A slight variation on this scenario is for CMDBf to succeed from a marketing perspective, as a checkmark that most vendors tick, but not as a true technology. This is the “smokescreen” scenario from Mr. Skeptic. One scenario that worries me is that CMDBf could fail because of the poor models of the CMDBs that implement it. If your IT model is not granular enough or if it matches the UI of your application more than the semantics of the IT components, then CMDBf will expose these shortcomings and probably be blamed for them (with bad models, “shoot the messenger” becomes “shoot the protocol”).

The second possible direction is that CMDBf provides enough value in integrating CMDBs that people want more and challenge the group to deliver on the “f” part, federation. That could take the form of a combination of:

  • better integration with other protocols (mostly from the WS-Management family, like WS-Enumeration and WS-Eventing),
  • reconciliation support (here are ways to address it),
  • some model transformations or canonical models,
  • some optimizations in the query mechanism for distributed queries (e.g. data partition rules).

The third possible direction (not exclusive) is for CMDBf to become the basis for a standard rule language for IT models. Yeah, another one (remember SML?). SPIN and SML show us how a generic query language can be used to support configuration rules. I very much like SPIN but it requires adopting RDF as a metamodel, which is a hard sell in XML-land. SML suffers technically from being too reliant on an inappropriate validation tool (XSD) and treating relationships as a second thought rather than an integral part of the model. Which is fine in many areas (EMF does it too), but not, in my view, when modeling IT systems.

If we are not going to use RDF/SPIN then let’s copy them. We can use the CMDBf metamodel (graph-based) where SPIN uses RDF. We can use the CMDBf query language (graph-oriented) where SPIN uses SPARQL. Since CMDBf queries use XPath, we see some commonalities with SML (which uses XPath through Schematron). But in CMDBf XPath is scoped to the leaf nodes of the graph, not the entire model as it is in SML. In other words, SML adds relationship traversal to XPath, while CMDBf adds XPath to its relationship-aware queries. It’s a matter of who’s on top. It sounds academic but it isn’t.

Does the industry really want standardized, re-usable configuration rules? SML/CML seem to say no. The push towards Cloud interop, on the other hand, begs for it. At least if you believe in programming your environment in a way that is partialy declarative rather than entirely procedural.

[UPDATED 2009/3/5: Rob England (a.k.a. Mr. Skeptic as I refer to him above) provides a geek-to-English translation for this post. Neat!]

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Filed under CMDB, CMDB Federation, CMDBf, DMTF, Everything, Graph query, IT Systems Mgmt, Mgmt integration, Modeling, RDF, SML, Specs, Standards, Tech, XPath

February 4, 2009

Oracle acquires mValent for application config management

mValent will become part of Enterprise Manager. It comes to complement other recent acquisition in the application management space: Auptyma, Moniforce, Empirix, ClearApp.

The announcement and FAQ are here.

More details about the acquired product and technology are on the mValent site, including here and here.

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Filed under Application Mgmt, CMDB, Everything, IT Systems Mgmt, Mgmt integration, Modeling, Oracle

January 12, 2009

A new SPIN on enriching a model with domain knowledge (constraints and inferences)

Back when I was at HP and we got involved with what turned into SML (now a W3C candidate recommendation), we tried to make a case for the specification to be based on RDF/OWL rather than XML/XSD/Schematron. It was a strange situation from a technical perspective because RDF is a better foundation for an IT model than XML, but on the other hand XSD/Schematron is a better choice for validation than OWL. OWL is focused on inference, not validation (because of both fundamental design choices, e.g. the open world assumption, and language expressiveness limitations).

So our options were to either use the right way to represent the system (RDF) combined with the wrong way to capture constraints (OWL) or to use the wrong way to represent the system (XML) combined with the right way to constrain it (mostly Schematron, with some limited help from XSD). At the end, of course, this subtle technical debate was crushed under the steamroller of vendor politics and RDF never got a fair chance anyway.

The point of this little background story is to describe the context in which I read this announcement from Holger Knublauch of TopQuadrant: the new version of their TopBraid Composer tool introduces SPIN, a way to complement OWL with a SPARQL-based constraint checking and inference mechanism.

This relates to SML in two ways.

First, there are similarities in the approach: Schematron leverages the XPath language, used to query XML, to create validation rules. SML then marries Schematron with XSD, for a more powerful validation mechanism. Compare this to SPIN: SPIN leverages the SPARQL query language, used to query RDF, to create validation/inference rules. SPIN also marries this with OWL, for a more powerful validation/inference mechanism.

But beyond the mirroring structures of SPIN and SML, the most interesting thing is that it looks like SPIN could nicely solve the conundrum, described above, of RDF being the right foundation for modeling IT systems but OWL being the wrong constraint mechanism. SPIN may do a better job than SML at what SML is aiming to do (validation rules). And at the same time, you get “for free” (or as close to “for free” as you can get with software, which is still far from “free”) a pretty powerful inference mechanism. The most powerful I know of, short of using a general programming language to capture your inference rules (and good luck with maintaining these rules).

This may sound like sci-fi, but it’s the next logical step for IT configuration standardization. Let’s look at where we are today:

  • SML (at W3C) is an attempt to standardize the expression of constraints.
  • CMDBf (at DMTF) is standardizing how the model content is queried (and, to some limited extent at this point, federated).
  • And recently IBM authored a proposal for a reconciliation specification for items in the model and sent it to an Eclipse group (COSMOS).

But once you tackle reconciliation, you are already half-way into inferencing territory. At least if you want to reconcile between models, not just between instances expressed in the same model. Because the models may not be defined at the same level of granularity, and before you can reconcile items you need to infer finer-grained entities in your coarser-grained model (or vice-versa) so that you can reconcile apples with apples.

Today, inferencing for IT models is done as part of the “discovery packs” that you can buy along with your IT management model repository. But not very well, in general. Because the way you write such a discovery module for the HP Universal CMDB is very different from how you write it for the BMC CMDB, IBM’s CCMDB or as a plug-in for Oracle Enterprise Manager or Microsoft System Center. Not to mention the smaller, more specialized, players. As a result, there is little incentive for 3rd party domain experts to put work into capturing inference rules since the work cannot be widely leveraged.

I am going a bit off-topic here, but one interesting thing about standardization of inferencing for IT management, if it happens, is that it is going to be very hard to not use RDF, OWL and some flavor of SPARQL (SPIN or equivalent) there. And once you do that, the XML-based constraint mechanisms (SML or others) are going to be in for a rough ride. After resisting the RDF stack for constraints, queries and basic reconciliation (because the added value was supposedly not “worth the cost” for each of these separately), the XML dam might get a crack for inferencing. And once RDF starts to trickle through that crack, the whole dam is going to come down in a big wave. Just to be clear, this is a prophetic long-term vision, not a prediction for 2009 (unfortunately).

In the meantime, I’d like to take this SPIN feature a… spin (sorry) when I find some time. We’ll see if I can install the new beta of TopBraid composer despite having used up, a year ago, my evaluation license of the earlier version of the product. Despite what I had hopped at some point, this is not directly applicable to my current work, so I am not sure I want to buy a license. But who knows, SPIN may turn out to be the change that eventually puts RDF back on my “day job” list (one can dream)…

It’s also nice that Holger took the pain to deliver SPIN not just as a feature of his product but also as a stand-alone specification, which should make it pretty easy for anyone who has a SPARQL engine handy to support it. Hopefully the next step will be for him to clarify the IP terms for the specification and to decide whether or not he wants to eventually submit it for standardization. Maybe to the W3C SML working group? :-) I’d have a hard time resisting joining if he did.

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Filed under CMDB, CMDBf, Everything, IT Systems Mgmt, Modeling, RDF, Semantic tech, SML, SPARQL, Specs, Tech, W3C

January 5, 2009

The art of reconciling items in your IT management model

Whether you call it a CMDB or some other name, any repository of IT model elements has the problem of establishing whether two entities are the same or not. Here is a quick map of the problem space.

Why there is no “one true solution”

There is no “true” answer to the “sameness” question. The following example illustrates this, even though it is not necessarily representative of datacenter scenarios. Ask any gamer to tell you the history of that 3-year-old PC under their desk. The power cord might be the only original piece left after they’ve upgraded the RAM, video card, sound card, hard disk(s), DVD drive and power supply. Not to mention the tragic overclocking accident that took the life of the motherboard/CPU. After the upgrade/replacement of each of these parts, the user still thought of the machine as the same PC, just upgraded/fixed. But how can it be the same as at the beginning if pretty much every single part has changed? And when time came to reinstall Windows, the registration probably failed because Microsoft decided that the same license was being used for a new machine. Sameness is in the eye of the beholder.

And it’s not just a hardware problem. When you upgrade your Oracle Database and start using a new ORACLE_HOME, it may feel like the same database to most users (including the applications that talk to the database) but a more executable-centric view might conclude that it is a new database.

Defining what makes an IT element unique is not a matter of truth. It’s a matter of usefulness for a given purpose. When trying to establish this for your model, if the conversation ever veers philosophical, you’re off track. This is engineering, not science. “A and B are the same” should be understood to be a shortcut for “it makes sense for my purpose to consider A and B to be the same”. Of course things become complicated when “my purpose” encompasses a whole set of use cases (add “management” after each of: performance, compliance, configuration, change, asset, business service, business transaction…).

How the problem arises

It can arise over time. For example the management agent has to be reinstalled and it forgets the id that had been assigned by the server. When it comes back up, it reports what looks like a new item. But you want to reconcile it with the historical data that came from the agent’s previous incarnation.

It can arise because you have different discovery channels for the same item. For example, a BPEL engine reports to the management server the processes it supports and that model includes the external Web services (partnerLink) invoked by the processes, thereby creating items for these external services in your repository. But some of those external services may be running on servers which you also monitor and the services (and more generally the applications that deliver them) may be separately discovered by the agents on these hosts, resulting in a potential duplicate representation in the repository.

Or the problem can be a result of the integration of IT management products. For example, that Dell server in my asset management system may be the same as the Linux host that runs my production database and appears in Oracle Enterprise Manager.

Fixing the mess

There are two stages to this:

First, you need some level of model alignment. In the general case, the different items that you are trying to reconcile are not expressed in the same model. The view of the server coming from the asset management system does not necessarily contain the same data as its view in your operations console. One contains the lease expiration date, the other one contains the amount of space left on the disk. Some data may be in both (e.g. number of CPUs, host name) but not necessarily in fields of the same name. Or with the same granularity (ownerName versus ownerFirstname +  ownerLastname). Not to mention type system differences (but if the items are already in the same repository you have presumably already forced some level of metamodel alignment). In short, you first have the challenge of model transformation, a more general problem. With the advantage that the entire model does not need to be translated for item reconciliation, only the subset of data needed to establish “sameness”: the identifying properties. And in some cases (e.g. when a standard model is used or when two instances of the same agent report on the item), the items to reconcile are already described in the same model and this step can be skipped.

Once the necessary level of model alignment has taken place (if needed) so that items can be compared, the real task of reconciliation takes place, based on domain knowledge. It could be through a set of scripts (Python’s mix of simplicity, portability, broad array of libraries and ease of integration make it shine in this usage). It could be through some kind of reconciliation taxonomy, like this draft that IBM has contributed to the Eclipse COSMOS project. Or through metadata such as WSDM’s correlatable properties. [BTW, as the spec editor I got to insert dubious cultural references in the specification (see the <print:PrinterResourcePropDoc> example in section 5.3.3.1), but let me assure you that I have since matured… ;-)]

These are not the only ways to reconcile items, but they are the approaches that can be followed based on just the data in the repository. Beyond that, you can run a dummy transaction and trace it (if possible) across different management systems to reconcile entities between them. There are plenty of other domain-specific tricks, depending on the item type (I remember a machine room, back in the days when each server had a CD drive, where a script to open the CD tray was used to allow the operator to put a sticker on the correct machine). In general, these approaches play on external variables that are not directly part of the model of the item and yet can be influenced through it. Similar to how the bulb temperature is used in this famous brain teaser. I guess the IT equivalent would be to load-stress an application and use IPMI to see which CPUs register a rise in temperature (note: not a recommended approach in production systems…).

Coming back to the IT model repository, you also need to have plumbing in place to deal with the result of the reconciliation: requests and data may come in that reference either one of the reconciled items and you need to be able to deal with that split personality, while providing a unified view in the general case. You also need to be ready to deal with potential data discrepancy between the items (either automatically or through of process that involves humans, but this is out of scope for this entry).

Preventing the mess from happening

Can’t we just prevent the problem from occurring in the first place? To some extent yes. The main way to prevent it is to not reconcile what doesn’t need to be. This may sound heretical in these days of “single source of truth” and “end to end visibility” but reconciliation of key connection points is often enough. You may not need to have one single model that contains everything from your company’s employee directory to the fan speed of all your servers. It’s a matter of delivering on use cases, not hoarding data.

When you do want to consolidate and reconcile, one approach is to standardize on natural IDs for items of different types. But this requires domain experts to carefully select identifying (and therefore immutable) properties of the different object types, which sounds a lot easier than it is. And it requires convincing others to adopt this approach, an even harder task. But as the proverb (almost) goes, one ounce of convention is worth one pound of reconciliation.

[Note: Whenever you talk about item reconciliation, the topic of correlating events is not far behind. It is assisted by a solid underlying IT model, but it has challenges of its own, so I’ll consider this out of scope for this discussion.]

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Filed under CMDB, Everything, IT Systems Mgmt, Mgmt integration, Modeling

October 30, 2008

First in-depth look at Microsoft’s Oslo and the “M” modeling language

Microsoft’s PDC is taking place this week and more details were shared with the attendees about project Oslo, an effort announced last year to drastically improve the use of models across the application lifecycle. Some code is available (I think the Quadrant code is only for PDC attendees but the Oslo SDK is available to everyone). I am not at PDC, I didn’t see any presentation and I didn’t download any code. But Microsoft has also posted technical details on MSDN and, as far as I am concerned, that’s the most time-effective way to spend a couple of hours learning about Oslo. BTW, the way they share these early design descriptions and accept to make their evolution public is admirable.

For those who only want to spend 10 minutes rather than 2 hours, here are the thoughts that came to my mind as I was reading.

Overall I am somewhat underwhelmed, but not necessarily in a bad way. I know that’s a little schizophrenic so let me explain. After hearing a lot about how Oslo was the next big thing in modeling, it is a little surprising to read a document that can be summarized as “modeling is good, so go create some SQL tables and store them in a RDBMS”. That’s the underwhelming part. But on the other hand, it is more down to earth and practically-minded than I feared. And this is just a summary, in truth there is more than just “use SQL”.

Half of the MSDN documentation basically explains how to use SQL Server to store application models (as of today, the “Developing Models for the Metadata Store” section has only one sub-section, “SQL Server Guidelines for Modeling in the Oslo Repository“). Does this mean that all .NET applications will eventually have to carry with them a deployment of SQL Server 2008 even if they don’t use it to store the their operational data? Sure there are a few extra repository services (e.g. finer-grained change auditing) but most Oslo repository services are generic SQL Server features. That section has quite a lot of T-SQL, but it’s pretty readable. It also has a lot of dependencies on following naming conventions which makes me think that directly creating T-SQL code is not the best approach.

Fortunately there is an alternative, the “M” language. It’s a schema language with a built-in constraint mechanism. I found it more data-oriented (as opposed to resource-oriented) than I expected. Even though “each model is really a set of data structures, relationships, and constraints in serialized form“, there is a lot more support for data structures and constraints than for relationships. It’s just a foreign key. Relationships aren’t items and don’t have any property (or “field” as they’re called in “M”). For example, the relationship between a student’s enrollment record and a given class can’t have, as property, the grade that the student got for that class (as in the example in section 4.1.4 of the second LC of SML). To model this in “M” you need to create another item (e.g. “courseEnrollment”) and have a relationship from the student to that item and another one from that item to the “course” item itself. Or to replace the foreign key in the student table with a complex structure that contains both the foreign key and the properties of the relationship. At the end it has the same expressiveness potential, but in a less streamlined form. I assume Microsoft took this approach for performance reasons.

I am going on a limb here, but it may also be a difference between development-time concerns and operation-time concerns. During development (all the way to testing and packaging), you can still mostly get away with a relatively simple containment structure. You care about the components of your application and how they are packaged inside or next to one another. Sure you care about who calls who outside of the deployment unit but that’s not as core a concern as getting your class dependencies right, your tests in order and your installer configured. In fact, some of the “who calls who” bindings will be only be realized at runtime. Oslo, at least so far, clearly seems more focused on development time than operations so support for a relationship-rich model may not seem critical. At operations time, on the other hand, you don’t really care so much about how things were packaged before installation. You care a lot more about who invokes who (especially for modern distributed applications), what the network layout is, what resources a ticket is attached to, etc. The model looks a lot more like a graph with complex relationships. Something that “M” doesn’t seem ideally suited for.

Except for this caveat, I like “M”. It’s not anti-XML (you can represent values as XML if you’d like) but it avoids the “the answer is XML/XSD what is the question” approach to modeling that is sometimes a little too prevalent. “M” is a much better schema language for IT systems than XSD. I especially like its approach to types. A value is not intrinsically of a given type. A type is a condition that you happen to meet or not at the current time (“take heart little field, you can be anything you want when you grow up”). As such, you can be of several types at the same time. Refined types are potatoes inside potatoes (not sure if “M” supports definition of types as unions and/or intersection of existing types, for intersection I want to write something like”type NewType : OldType1 where this in OldType2” but there is no “this” in “M”). That approach to types (and the way constraints leverage types) is reminiscent of RDF/OWL. It’s a classification more than a typification, but I understand why they didn’t want to call it “class”. The similarities with RDF/OWL don’t go any further. As I wrote earlier, “M”is very data-focused and not resource-focused: as far as I can tell “M” types are defined syntactically, not semantically (the semantics come as a consequence). For example, I don’t think that you can assert that a given item representing a person is of type “friendly” if there is no corresponding data in the item. You’d have to first create a boolean field called “friendly” and define that those that have that field set to “true” are of type “friendly”. Unlike in RDF/OWL where you can just assert that a subject is “friendly”.

Here is another reason why you can’t have “semantics-only” types: “if you do not specify the type of a field or value, M infers a type for it“. Two things don’t sound quite right to me here. First a detail: the sentence (like others in the doc) talks about “the” type of a field of value, while there can be more than one. More importantly, what’s the point of this feature? How does it help me to have my IRC nickname classified as a post code or as a password just because it happens to be made of a compatible combination of letters and numbers? Maybe it makes sense as a storage optimization, but why does it make sense to expose this to the user?

I also like the way “extents” work. The current description of that feature is pretty limited, but based on how it is used in other parts I think one of its usages is to support a non-OO equivalent to inheritance: create two extents, one for the “superclass” and one for the “subclass” where each only contains the properties/fields defined at that level. You should get both of them in order to have the full picture (all the fields). This is, if I understand it correctly, similar to something I have been (unsuccessfully so far because “XML doesn’t do it this way”) trying to sell to the DMTF CMDBf working group: model inheritance through a set of non-overlapping records rather than dealing with a type hierarchy on record types. It’s not just that it makes relational storage easier (even though it does and that’s probably why “M” does it this way), it also makes your query/select operations a lot easier to specify and implement.

All in all (and without having gone through the exercise of defining actual models in “M”), it seems like a fine schema language (except that its dependency on the CLR base types is unpractical for users outside of the Microsoft universe) but I am not sure if it is beefy enough to be a good IT management metamodel. When the document says that “the Oslo repository provides open and flexible access to the data it contains, which enables direct access to SQL Server views of the underlying data. There are no complex data access layers or APIs” it sounds better than saying “it’s just SQL, so map your model to it and if you want relationships or type inheritance just build it on top of it and quit whining”. But it is an admission of limitation at the same time as a claim of simplicity. I also smell an assumption that LINQ will provide enough hand-holding that non-SQL-savvy developers will be ok. We’ll see.

And then there is MGrammar. Things get a little confusing at that point if you try to relate MGrammar to “M”. Actually, the FAQ states that “the M language consists of three parts: MGraph, MSchema and MGrammar“. This came a bit as a surprise to me since at that point I had finished reading (not in details but not too quickly either) the “M” documentation and I hadn’t seen these names mentioned once. Looks like there is some documentation consistency issues here, but that’s hardly surprising considering this is a “hyper-early (pre-alpha)” release as Doug Purdy puts it.

I think that everything that I have referred to as “M” above is MSchema.

MGrammar is something different altogether: it’s the source of the Domain Specific Language (DSL) references we’ve been hearing in relationship with Oslo. Technically, MGrammar is a BNF on steroids plus an automatically generated parser for your syntax. Cute. I assume that “M” (i.e. MSchema) is built as MGrammar-defined DSL but I am not sure why I would care. I am all for reuse and if someone at Microsoft thought that there was something reusable in the way they defined MSchema then it’s a good thing to expose this tool. But where does it come into play in application modeling? The last thing I want is people inventing completely independent languages to describe different domains. I am all for specialization, but a common underlying metamodel is pretty nice when you have to make sense of a whole system. I don’t see any such commonality in MGrammar: as far as I can tell it can be used to define anything from PostScript to sonnets.

From the FAQ, the connection point between MGrammar and MSchema is MGraph (MGrammar languages are parsed into an MGraph, MSchema “builds on MGraph”). That’s nice, but since neither the MSchema nor the MGrammar documentation mention MGraph I don’t really know what to make of this. David Chappell’s white paper also mentions MSchema and MGrammar but not MGraph. The introduction to the MGrammar Language Specification states that “the data that results from Mg [a.k.a. MGrammar] processing is compatible with Mg’s sister language, The Oslo Modeling Language, M, which provides a SQL-compatible schema and query language that can be used to further process the underlying information“. Compatible? I need more information here. In any case, MGrammar sounds like a fun project for a techie. Who am I to deny Microsoft engineers their fun. Jokes aside, I am probably missing something here seeing how prevalent the DSL message is in all discussions of Oslo. Look at the “highlights of this book” section for the upcoming Oslo/M book from the creators of the “M” language: half of it is about the DSL support and there must be a reason beyond pure geekery. As a side note, if you buy this book you need to understand what little shelf life it will have (I can give you a good price on a lightly-used Hailstorm/”.Net my services” specification book).

Aside from the “M” language itself, there are a few models described in the documentation. One corresponds to BPMN (actually, it says that it “closely aligns with” BPPMN 1.1, does this imply that they are not quite the same?). The fact that this model supports imports from Visio is a nice feature.

The Application model (one of the places where you can see “extents” in action) scares me a little bit because I doubt that two different people would use the same “extents” to describe the same software elements. Unless of course that’s being done for them by a pre-defined mapping to their development framework (.NET) enacted by their common development tool (Visual Studio). Which may be the assumption. Yet, the Application model is defined in generic terms, not Microsoft-specific (with a couple of slip-ups, like a WebApplicationModule being defined as a “Web application (module) implemented by IIS or WAS“. Maybe I’ll feel better about the generic applicability of this Application model when I see a full-fledged description (e.g. including relationship semantics as captured in foreign key field names) and an example.

At the bottom of that Application model, there is a lonely “Manageable” type to use if you have a LifecycleState field. This reinforces my impression that despite the claims to link development time with operational time, a lot of the focus to date has been on the former rather than the latter.

The ServiceModel model will look familiar to people familiar with SCA and is presumably complementary to the WorkflowModel and WorkflowServiceModel models, both of which are directly mapped to Windows Workflow Foundation. I guess that’s where Oslo and Dublin touch one another. I am still glad they are now clearly separated.

There is also a “Quadrant” model which concerns me a bit (it seems to be used to store customization of the Quadrant UI which, while convenient to store straight in the repository, doesn’t strike me as necessarily belonging there).

At this point, the question is not whether Microsoft can build Oslo as it is currently defined. SQL Server 2008 already exists, the usage guidelines aren’t unrealistic and even the “M-to-T-SQL” translation doesn’t seem too hard for Microsoft to implement (the SDK presumable already contains an implementation). I have no doubt they can deliver the system they describe. What I don’t know is whether and how it will be actually useful.

Describing “M” in details is good. Describing how the repository is implemented on top of SQL Server 2008 is interesting but not so relevant. What I’d like to see is a description of how all this gets used. How does it change the Visual Studio experience? How does it change the installation process/format? How does it support round-tripping between lifecycle stages (e.g. if the developer changes the workflow model, does that original BPMN model get consequently updated)? How does it relate to SLAs and policies? How does it apply to application monitoring? How does it apply to configuration management, to the change process? Etc. In short, what’s the Oslo ecosystem going to be.

These questions aren’t completely ignored in the MSDN documentation, but they are dispensed with in a couple of pages: “Application Development and Lifecycle Improvements” and “IT Operations Benefits“. The former states, for example, that “having the Oslo repository act as a central location for these models also enables a connection between the design and implementation models. This connection helps prevent these models from becoming disconnected during the development process“. Which all sounds good but is just a set of assertions that we have heard many times before (not just from Microsoft). How do “M” and the Oslo repository really make this true?

On the “IT Operations Benefits” side, things are equally blurry: “the Oslo repository can store all types of machine and application configuration data. When consistently updated, this configuration data is a catalog of the current state of all monitored machines and applications in the environment“. Notice the “when consistently updated” hand wave. That’s kind of the crux if you really want to manage across the lifecycle. How will they achieve this consistency? By centralizing all changes through a model-driven controller a la SDM/SML? Through ongoing discovery and/or change notifications? By relying on good old ITIL/MOF processes?

The FAQ declares that “having a common approach does not necessarily correlate to one physical store, but more of a federated model and we believe that some of the new Repository, along with existing investments in both Configuration Management Database (CMDB) and Team Foundation Server (TFS), will form the foundation for a common Microsoft metadata strategy and should be supported across our set of products“. OK, but who is the source of truth for application configuration data? The Oslo repository or the CMDB? Is one the desired state and the other the observed state? Does the CMDB go back to simply being a Service Desk (and if so, does the Oslo repository take on the responsibility to enforce change processes, something that requires more than the security model in Oslo)? If the CMDB is still going to use SML as its metamodel, how do you efficiently federate across such different metamodels as SML (i.e. XSD + schematron + relationships) and “M”?

Lots of questions remaining. What will Oslo have turned into in a few years? A business process design/implementation/monitoring suite (there is a strong workflow feel to many parts)? A generic drag-and-drop programming environment (“the fact that entire features are already described by models means that for a wide array of application and component categories you can start using visual tools to design and implement your components“)? A control center for end to end application management? All of the above? Nothing?

This was just a quick brain dump after reading the documents. Actually, I just realized it somehow got pretty long (congrats if you’re still reading). I hope this post is not too disorganized. Oslo is an interesting effort, but, as Microsoft is first to admit, it’s at a very early stage. I am just surprised that this first release spends so much time on the “how” rather than the “what”. Maybe it’s just because I only got my information from the MSDN documentation. We’ll see when more content from PDC finds its way online. I just want the slides, watching recorded presentations is rarely time-efficient (and you can expect them to require Silverlight).

Speaking of Silverlight, there is this new site on Oslo if you think watching some videos is worth installing Silverlight. Those screenshots don’t motivate me sufficiently.

[UPDATED 2008/10/30: Rather than going to bed I Googled around a bit and found a  post by Martin Fowler that answers some of my questions about MGrammar, MGraph and MSchema. MGraph is for instances, MSchema is for types. It answers some plumbing question, but I still have questions about expected usage and relevance to applications modeling.]

[UPDATED 2008/10/30: I also found the recordings and slides from past PDC sessions. Nice job Microsoft for this quick turnaround time, even if you require Sliverlight and/or the PPTX viewer. The sessions are:

  • TL23 A Lap around “Oslo” (Doug Purdy, Vijaye Raji)
  • TL27 “Oslo”: The Language (Don Box, David Langworthy)
  • TL18 “Oslo”: Customizing and Extending the Visual Design Experience (Don Box, Florian Voss)
  • TL28 “Oslo”: Repository and Models (Chris Sells)

The first two sessions (deliverd Tuesday) have a replay and slides, the others should, I assume, follow soon.]

[UPDATED 2008/11/3: A nice overview of Oslo by Aaron Skonnard. Unlike most other Oslo articles over the last week, this one tries to paint the (yet-to-be-realized) full picture of the Oslo ecoystem. He mentions that “other Microsoft products and technologies are expected to build on Oslo to provide other runtimes. A few that have already been announced include Microsoft System Center (Operations Manager) and Team Foundation Server (TFS) in Visual Studio Team System”. It’s interesting that he qualifies System Center to be more specifically “operations manager” rather than “configuration manager” but I wouldn’t read too much into it at this point.]

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Filed under Application Mgmt, BPM, Business Process, CMDB, Everything, IT Systems Mgmt, Manageability, Mgmt integration, Microsoft, Middleware, Modeling, Oslo, SML, Specs, Tech

September 8, 2008

CMDBf interop demo

IBM and CA are apparently showing an interoperability demo between their respective CMDBs at itSMF Fusion this week. I am not there to see it, but they describe it (it’s a corporate merger scenario) in this press release. It is presumably based on the version of the specification that was submitted to DMTF.

More information about CMDBf, along with another demonstration, will be available in a couple of months for ManDevCon attendees. Three sessions are on the agenda, all in a row and in the same room (so make sure to get a good seat, i.e. one close to a power plug, from the start):

  • CMDB Federation Overview (Vince Kowalski, BMC and Marv Waschke, CA)
  • CMDB Federation Technical Description (Mark Johnson, IBM and Marv Waschke, CA)
  • CMDB Federation Demonstration (Mark Johnson, IBM and Dave Snelling, Fujitsu)

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Filed under CA, CMDB, CMDB Federation, CMDBf, Conference, DMTF, Everything, IBM, IT Systems Mgmt, ITIL, Mgmt integration, Specs, Standards, Trade show

July 15, 2008

Did someone at EDS miss the memo?

Two months ago, HP announced the acquisition of EDS.

One month later, HP Software announced a slew of new service management products, including an updated version (7.5) of Universal CMDB (from the Mercury acquisition).

One month later (today), according to BMC (with supporting quote from an EDS exec), “EDS Asia Pacific Standardises on BMC Software Atrium CMDB to Improve Service Delivery”.

As an ex-colleague pointed out to me, the acquisition isn’t closed yet. Still.

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Filed under BSM, CMDB, Everything, HP, IT Systems Mgmt

June 17, 2008

BMC acquires ITM Software

Another BMC acquisition today: ITM Software. Their software suite is designed to help drive IT decisions from the point of view of their business impact.

This is important, of course, for all the reasons that BMC, HP, Oracle and others have been explaining for a while (how often have you heard the word “alignment” over the last three years, compared to the previous thirty?). It’s becoming even more important now, as the options for IT sourcing (from the traditional “give it all to Unisys”, to SaaS, to running your own apps in a utility computing environment…) are multiplicating. Choosing between Intel and AMD CPUs in your datacenter is a technical decision, but choosing between an on-premise application, a SaaS application and running your application on EC2 is driven by business considerations of cost, risks, control, flexibility, etc. And it’s not just a one-time decision, it’s the day to day management that follows these decisions.

I don’t know much about the current ITM offering, but it was never clear to me how much they could deliver as a narrow layer, separate from the heavy-duty IT management stack (I can see how they would deliver financial and project management tools, but what about *really* linking day to day IT administration decisions to the business impact). Being part of BMC, presumably allowing deeper integration into real IT management operations, seems to make sense.

I just wish they didn’t make it sound so easy: “BMC’s purchase of ITM Software creates a unique, integrated solution that provides customers with a single comprehensive view into…”. So just signing the check creates the integration? Now I am going to get calls from our execs asking why it takes so much work to integrate acquired products, if BMC can do it the same day they sign the deal…

While I am at it, here is the press release that HP put out to list the announcements at their Software Universe conference this week. I notice that it’s all about new versions of ex-Mercury products. No OpenView, Peregrine or Opsware content, as far as I can tell. Without looking at it in more details I don’t know how different these new versions really are. What appears pretty new is the SaaS offering (also based on Mercury products) at the end of the press release. On the nitpicking side, can anyone tell me what these “static configuration management databases” are that are “unable to support the real-time needs of today’s complex technology environments”? I can see how a “static” database would be hard-pressed to help, but I haven’t noticed any vendor selling read-only config stores.

[UPDATED 2008/6/18: More details about the HP announcement at InfoWorld. Including quotes from my ex-boss Ramin. Congrats on getting UCMDB 7.5 out of the door!]

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Filed under Application Mgmt, BSM, Business, CMDB, Everything, HP, IT Systems Mgmt, ITIL, Mgmt integration

May 20, 2008

I have seen the future of CMDBf

I got a sneak peak at CMDBf v2 today.

I am calling it v2 based on the assumption that the one being currently standardized in DMTF will end up being called 1.0 (because it’s the first one out of DMTF) or 1.1 (to prevent confusion with the submitted version).

At the Semantic Technology Conference, David Booth from HP presented his work (along with his partner, Steve Battle from HP Labs) to provide a SPARQL front-end to HP’s Universal CMDB (the engine under what was the Mercury MAM product). Here are the slides.

The mapping from SPARQL to TQL (the native query interface for UCMDB) was made pretty easy by the fact that TQL is a graph-oriented query language. How much harder would it be to similarly transform a CMDBf (v1) query interface into a SPARQL query interface (and vice-versa)? Not much. The only added difficulty would come from the CMDBf XPath constraints. TQL has a property value mechanism that is very similar to CMDBf’s “propertyValue” constraint and maps well to SPARQL functions. The introduction of XPath as a constraint language in CMDBf makes things harder. It could be handled by adding XPath support to the SPARQL engine using function extensibility. Or by turning the entire XML into RDF and emulating XPath in SPARQL. But in either case, you’ll have impedence mismatch at some point because concepts such as element order that exist in XPath have no native equivalent in RDF.

The use of XPath in selectors on the other hand is not a problem. HP’s prototype uses Gloze (available as a Jena package) to turn the XML returned by UCMDB into RDF. An XSLT transform could turn that same XML into a CMDBf-valid XML response instead and that XSLT could easily handle the XPath selectors from the query request. This is another reason why constraints and selectors should remain separate in CMDBf (fortunately the specification is back to doing this properly).

Here is why I call this prototype CMDBf v2: The CMDBf effort (v1 or 1.1), in its current form of re-inventing a graph query, can succeed. Let’s assume the working group strikes a reasonable balance between completeness and complexity, and vendors choose to compete on innovation and execution rather than lock-in (insert cynical comment here). CMDBf may then end up being supported by the main CMDB vendors. It wouldn’t provide federation capabilities, but having a common CMDB query interface supported by the Big Four would help with management integration. And yet, while the value would be real, it would only provide a little help to solve a larger problem:

  • As a technology limited to IT systems management, it would be unlikely to see widely available tools (e.g. user consoles and language-specific libraries).
  • It wouldn’t get the kind of robustness and interoperability that comes from wide adoption. While pretty similar, there might be some minor differences in the various implementations. Once your implementation has been tweaked to work with the implementations from the Big Four, you’ll call it done. Just like SNMP, another technology that is specific to IT systems management (see it happen here).
  • Even if it works perfectly at the query level, it will just hasten the time when developers run into the real problem, model interoperability. CMDBf doesn’t help at all with this. In fact, it makes it harder by hard-coding some dependencies on an XML back-end (the XPath constraints).

In the long run, IT management has to become more automated and integrated. That’s a given. The way it happens may or may not go through CMDB-like configuration stores. But if it does, we’ll have to eventually move beyond CMDBf (v1) towards something that addresses the three requirements above. And federation. I don’t know if it will be called CMDBf v2, and/or if it will come from the DMTF (by then, the CMDBf brand might be an asset or a liability depending on developer experience with the specification). But I strongly suspect (“probability 0.8” as a Gartner analyst might put it) that it will use semantic technologies. Because the real, hard, underlying problem is a problem of semantic integration. In that sense, David and Steve’s prototype is a sneak peek at what will come after CMDBf v1/1.1.

Pretty much since the beginning of CMDBf I have been pushing for it to ideally embrace SPARQL (with no success) or to at least stay close to it conceptually in order to make the eventual mapping/evolution smooth (with a bit more success). This includes pushing for a topological query language, trying to keep XML idiosyncrasies at bay and keeping constraints and selectors cleanly separated. Rather than working within the CMDBf group, David took the alternative approach of simply doing it. Hopefully this will help convince people of the value of re-using semantic web technology for IT systems management. Yes semantic technologies have been designed for a much more general use case. But the use cases that CMDB systems address are a subset of the use cases addressed by semantic technologies. It’s hard for domain experts to see their domain as just a subset of a larger problem, but this is the case here. Isn’t HTTP serving the IT management community better than a systems management-specific alternative would?

By the way, there is no inferencing taking place in the HP prototype. We are just talking about re-using an existing, well though-through graph query language. Sure OWL inferencing and some rules could be seamless layered on top of this. But this is in no way required to do (better) what CMDBf v1 tries to do.

And then there is the “federation” question. Who do you trust more to deliver this? A bunch of IT system management architects in DMTF or the web and query experts at W3C, HP Labs etc who designed and implemented SPARQL over many years? BTW, it sounds like SPQARL federation was discussed at WWW 2008, based on these meeting notes (search for “federation”).

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Filed under Automation, CMDB, CMDB Federation, CMDBf, Conference, DMTF, Everything, Graph query, HP, IT Systems Mgmt, Query, RDF, Semantic tech, SPARQL, Standards, W3C, XPath

April 29, 2008

Oracle/BEA, WS-Management and MMS: announcements of the day

A few announcements came out today.

The good news: Oracle’s acquisition of BEA closes. Unobstructed technical work can start.

The conveniently-timed news: WS-Management officially a standard.

Speaking of MMS 2008, any announcement there? Not much so far, as explained by Ian Blyth. If I parse the cross-platform part of the press release correctly, it says that management of non-Windows resources by Operations Manager is based on WS-Management, but WS-Management alone is not enough so Microsoft is providing a development kit for several non-Microsoft operating systems. It will be interesting to see what exactly is produced by these management packs. Can they be called on by management tools other Operations Manager or is the stuff that rides on top of WS-Management too proprietary to allow this? No word on SML/CML.

By the end of the week we may have a clearer picture, including what’s going on with the previously-announced reset on System Center Service Manager. Coté is on the scene and will undoubtedly share his thoughts.

As a side note, the way the MMS main page loads betrays the fact that, in 2008, Microsoft (or more likely its event marketing contractor) is using the same clueless HTML design approach that I first saw in 1995 and recently wrote about. All the text in the center of the MMS home page is contained in one large picture (available here). They didn’t even bother with a “ALT” field, so good luck to blind users. The part that says “Registration Overview Page” was made blue and underlined to suggest that it is a link, but it is just a part of the picture. Which, presumably, was supposed to be turned into a link using an image map. Well, turns out they can’t even get that right.

They tried to use a client-side image map (not available in 1995) but somehow the actual map code is commented out in the HTML source:

<!--<map name=Map>
  <area shape=RECT coords=18,549,210,572 href="registrationoverview.aspx">
  <area shape=RECT coords=17,596,222,634 href="registrationoverview.aspx">
</map>-->

As a result, the single most preeminent link on the home page is dead. And there is no server-side image map mechanism as a backup (which I remember used to be best practice when client support for client-side image maps was spotty).

Looking at the HTML source also reveals that tables are over-used. That’s the kind of HTML I can write, and I don’t mean that as a compliment.

[UPDATED 2008/5/5: As expected/hoped, Coté did share his thoughts on this “cross-platform” move from the MMS floor.]

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Filed under CMDB, DMTF, Everything, IT Systems Mgmt, Linux, Manageability, Microsoft, Oracle, Standards, Trade show

February 13, 2008

Microsoft ditches SML, returns to SDM?

I gave in to the temptation of a tabloid-style title for this post, but the resulting guilt forces me to quickly explain that it is speculation and not based on any information other than what is in the links below (none of which explicitly refers to SDM or SML). And of course I work for a Microsoft competitor, so keep your skeptic hat on, as always.

The smoke that makes me picture that SML/SDM fire comes from this post on the Service Center team blog. In it, the product marketing manager for System Center Service Manager announces that the product will not ship until 2010. Here are the reasons given.

“The relevant feedback here can be summarized as:

  • Improve performance
  • Enhance integration with the rest of the System Center product family and with the wider Microsoft product offering

To meet these requirements we have decided to replace specific components of the Service Manager infrastructure. We will also take this opportunity to align the product with the rest of the System Center family by taking advantage of proven technologies in use in those products”

Let’s rewind a little bit and bring some context. Microsoft developed the Service Definition Model (SDM) to try to capture a consistent model of IT resources. There are several versions of SDM out there, and one of them is currently used by Operations Manager. It is how you capture domain-specific knowledge in a Management Pack (Microsoft’s name for a plug-in that lets you bring a new target type to Operations Manager). In order to get more people to write management packs that Operations Manager can consume, Microsoft decided to standardize SDM. It approached companies like IBM and HP and the SDM specification became SML. Except that there was a lot in SDM that looked like XSD, so SML was refactored as an extension of XSD (pulling in additions from Schematron) rather than a more stand-alone, management-specific approach like SDM. As I’ve argued before (look for the “XSD in SML” paragraph), in retrospect this was the wrong choice. SML was submitted to W3C and is now well advanced towards completion as a standard. Microsoft was forging ahead with the transition from SDM to SML and when they announced their upcoming CMDB they made it clear that it would use SML as its native metamodel (“we’re taking SML and making it the schema for CMDB” said Kirill Tatarinov who then headed the Service Center group).

Back to the present time. This NetworkWorld article clarifies that it’s a redesign of the CMDB part of Service Center that is causing the delay: “beta testing revealed performance and scalability issues with the CMDB and Microsoft plans to rebuild its architecture using components already used in Operations Manager.” More specifically, Robert Reynolds, a “group product planner for System Center” explains that “the core model-based data store in Operations Manager has the basic pieces that we need”. That “model-based data store” is the one that uses SDM. As a side note, I would very much like to know what part of the “performance and scalability issues” come from using XSD (where a lot of complications come from features not relevant for systems management).

Thus the “enhance integration with the rest of the System Center product family” in the original blog post reads a lot like dumping SML as the metamodel for the CMDB in favor of SDM (or an updated version of SDM). QED. Kind of.

In addition to the problems Microsoft uncovered with the Service Center Beta, the upcoming changes around project Oslo might have further weakened the justification for using SML. In another FUD-spreading blog post, I hypothesized about what Oslo means for SML/CML. This recent development with the CMDB reinforces that view.

I understand that there is probably more to this decision at Microsoft than the SML/SDM question but this aspect is the one that may have an impact not just on Microsoft customers but on others who are considering using SML. In the larger scheme of things, the overarching technical question is whether one metamodel (be it SDM, SML, MOF or something else) can efficiently be used to represent models across the entire IT stack. I am growing increasingly convinced that it cannot.

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Filed under CMDB, Everything, IT Systems Mgmt, Microsoft, Oslo, SML, Specs, Standards

November 28, 2007

CMDBf now in the hands of the DMTF

It’s now official, the CMDBf specification has been submitted to the DMTF and will be standardized there. Here is the press release and here is the specification (unchanged) republished on the DMTF site. The CMDBf working group was created a while ago at the DMTF but I didn’t report it since it wasn’t clear to me whether that was public information or not. The press release makes this clear now.

As a side note, this is one of my ongoing frustrations with the DMTF. Almost everything happens in private with no publicly-accessible URL until a press release comes out and of course lots of interesting things happen that don’t get a press release. I have heard many times that the DMTF is working on opening up the process, but I still haven’t seen much change. If this had been OASIS or W3C, the call for formation of the new working group would have been publicly accessible even before the group was created. OK, end of ranting.

As always, there isn’t much useful information to be gleaned from the text of the press release. Only that, as expected, the authors addressed the question of how this relates to CIM, since for many DMTF=CIM. So the press release proactively declares that the CMDBf work will not be limited to CIM-modeled configuration data. What this means in practice will be seen later (e.g. will there be CIM-specific extensions?).

Having seen how executive quotes for press releases get generated I hate to read too much into them, but another thing I can’t help noticing in the press release is that none of the quotes from the companies submitting the specification tout federation, but simply “integration” or “sharing”. For example: “integration and interoperability” (BMC), “share data” (CA), “sharing of information” (HP), “view, track and change information” (IBM), “exchange data” (Microsoft). This more realistic assessment of what the specification does stands in contrast to the way the DMTF presents it in the press release : “this specification provides a standard way to federate management data stored in multiple different data models”. At this point, it doesn’t really provide federation and especially not across different models.

All in all, it’s as good thing for this work to be moved to a standards organization. I may join the CMDBf group at the DMTF to track it, but I don’t plan to engage very much as this area isn’t my focus anymore now that I am at Oracle. But of course everything is linked at some level in the management field.

[UPDATE  on 2007/11/30: two days after posting this message I got the monthly DMTF newsletter which touches on points I raise here. So here are the relevant links. First, Mike Baskey, DMTF Chairman, shares his view on what CMDBf means for DMTF. Second, as if to respond to my rant on the opacity of the DMTF, Josh Cohen, DMTF Vice-chairman, gives an update on process improvements. Some progress indeed, but still a far cry from opening up mailing list archives so that observers can see in real time what issues are addressed and can go back in time to understand how a specific technical decision was made and what were the considerations.]

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Filed under CMDB, CMDB Federation, CMDBf, DMTF, Everything, IT Systems Mgmt, ITIL, Specs, Standards