Category Archives: Mgmt integration

February 2, 2012

Come for the PaaS Functional Model, stay for the Cloud Operational Model

The Functional Model of PaaS is nice, but the Operational Model matters more.

Let’s first define these terms.

The Functional Model is what the platform does for you. For example, in the case of AWS S3, it means storing objects and making them accessible via HTTP.

The Operational Model is how you consume the platform service. How you request it, how you manage it, how much it costs, basically the total sum of the responsibility you have to accept if you use the features in the Functional Model. In the case of S3, the Operational Model is made of an API/UI to manage it, a bill that comes every month, and a support channel which depends on the contract you bought.

The Operational Model is where the S (“service”) in “PaaS” takes over from the P (“platform”). The Operational Model is not always as glamorous as new runtime features. But it’s what makes Cloud Cloud. If a provider doesn’t offer the specific platform feature your application developers desire, you can work around it. Either by using a slightly-less optimal approach or by building the feature yourself on top of lower-level building blocks (as Netflix did with Cassandra on EC2 before DynamoDB was an option). But if your provider doesn’t offer an Operational Model that supports your processes and business requirements, then you’re getting a hipster’s app server, not a real PaaS. It doesn’t matter how easy it was to put together a proof-of-concept on top of that PaaS if using it in production is playing Russian roulette with your business.

If the Cloud Operational Model is so important, what defines it and what makes a good Operational Model? In short, the Operational Model must be able to integrate with the consumer’s key processes: the business processes, the development processes, the IT processes, the customer support processes, the compliance processes, etc.

To make things more concrete, here are some of the key aspects of the Operational Model.

Deployment / configuration / management

I won’t spend much time on this one, as it’s the most understood aspect. Most Clouds offer both a UI and an API to let you provision and control the artifacts (e.g. VMs, application containers, etc) via which you access the PaaS functional interface. But, while necessary, this API is only a piece of a complete operational interface.

Support

What happens when things go wrong? What support channels do you have access to? Every Cloud provider will show you a list of support options, but what’s really behind these options? And do they have the capability (technical and logistical) to handle all your issues? Do they have deep expertise in all the software components that make up their infrastructure (especially in PaaS) from top to bottom? Do they run their own datacenter or do they themselves rely on a customer support channel for any issue at that level?

SLAs

I personally think discussions around SLAs are overblown (it seems like people try to reduce the entire Cloud Operational Model to a provisioning API plus an SLA, which is comically simplistic). But SLAs are indeed part of the Operational Model.

Infrastructure change management

It’s very nice how, in a PaaS setting, the Cloud provider takes care of all change management tasks (including patching) for the infrastructure. But the fact that your Cloud provider and you agree on this doesn’t neutralize Murphy’s law any more than me wearing Michael Jordan sneakers neutralizes the law of gravity when I (try to) dunk.

In other words, if a patch or update is worth testing in a staging environment if you were to apply it on-premise, what makes you think that it’s less likely to cause a problem if it’s the Cloud provider who rolls it out? Sure, in most cases it will work just fine and you can sing the praise of “NoOps”. Until the day when things go wrong, your users are affected and you’re taken completely off-guard. Good luck debugging that problem, when you don’t even know that an infrastructure change is being rolled out and when it might not even have been rolled out uniformly across all instances of your application.

How is that handled in your provider’s Operational Model? Do you have visibility into the change schedule? Do you have the option to test your application on the new infrastructure or to at least influence in any way how and when the change gets rolled out to your instances?

Note: I’ve covered this in more details before and so has Chris Hoff.

Diagnostic

Developers have assembled a panoply of diagnostic tools (memory/thread analysis, BTM, user experience, logging, tracing…) for the on-premise model. Many of these won’t work in PaaS settings because they require a console on the local machine, or an agent, or a specific port open, or a specific feature enabled in the runtime. But the need doesn’t go away. How does your PaaS Operational Model support that process?

Customer support

You’re a customer of your Cloud, but you have customers of your own and you have to support them. Do you have the tools to react to their issues involving your Cloud-deployed application? Can you link their service requests with the related actions and data exposed via your Cloud’s operational interface?

Security / compliance

Security is part of what a Cloud provider has to worry about. The problem is, it’s a very relative concept. The issue is not what security the Cloud provider needs, it’s what security its customers need. They have requirements. They have mandates. They have regulations and audits. In short, they have their own security processes. The key question, from their perspective, is not whether the provider’s security is “good”, but whether it accommodates their own security process. Which is why security is not a “trust us” black box (I don’t think anyone has coined “NoSec” yet, but it can’t be far behind “NoOps”) but an integral part of the Cloud Operational Model.

Business management

The oft-repeated mantra is that Cloud replaces capital expenses (CapExp) with operational expenses (OpEx). There’s a lot more to it than that, but it surely contributes a lot to OpEx and that needs to be managed. How does the Cloud Operational Model support this? Are buyer-side roles clearly identified (who can create an account, who can deploy a service instance, who can manage a deployed instance, etc) and do they map well to the organizational structure of the consumer organization? Can charges be segmented and attributed to various cost centers? Can quotas be set? Can consumption/cost projections be run?

We all (at least those of us who aren’t accountants) love a great story about how some employee used a credit card to get from the Cloud something that the normal corporate process would not allow (or at too high a cost). These are fun for a while, but it’s not sustainable. This doesn’t mean organizations will not be able to take advantage of the flexibility of Cloud, but they will only be able to do it if the Cloud Operational Model provides the needed support to meet the requirements of internal control processes.

Conclusion

Some of the ways in which the Cloud Operational Model materializes can be unexpected. They can seem old-fashioned. Let’s take Amazon Web Services (AWS) as an example. When they started, ownership of AWS resources was tied to an individual user’s Amazon account. That’s a big Operational Model no-no. They’ve moved past that point. As an illustration of how the Operational Model materializes, here are some of the features that are part of Amazon’s:

  • You can Fedex a drive and have Amazon load the data to S3.
  • You can optimize your costs for flexible workloads via spot instances.
  • The monitoring console (and API) will let you know ahead of time (when possible) which instances need to be rebooted and which will need to be terminated because they run on a soon-to-be-decommissioned server. Now you could argue that it’s a limitation of the AWS platform (lack of live migration) but that’s not the point here. Limitations exists and the role of the Operational Model is to provide the tools to handle them in an acceptable way.
  • Amazon has a program to put customers in touch with qualified System Integrators.
  • You can use your Amazon support channel for questions related to some 3rd party software (though I don’t know what the depth of that support is).
  • To support your security and compliance requirements, AWS support multi-factor authentication and has achieved some certifications and accreditations.
  • Instance status checks can help streamline your diagnostic flows.

These Operational Model features don’t generate nearly as much discussion as new Functional Model features (“oh, look, a NoSQL AWS service!”) . That’s OK. The Operational Model doesn’t seek the limelight.

Business applications are involved, in some form, in almost every activity taking place in a company. Those activities take many different forms, from a developer debugging an application to an executive examining operational expenses. The PaaS Operational Model must meet their needs.

2 Comments

Filed under Amazon, API, Application Mgmt, Automation, Business, Business Process, Cloud Computing, Everything, Manageability, Mgmt integration, PaaS, Utility computing

December 15, 2011

Everything is PaaSible

That’s the title of an article I wrote for InfoQ and which went live today.

If you can get past the punny title you’ll read about the following points:

  • In traditional (and IaaS) environments, many available application infrastructure features remain rarely used because of the cost (perceived or real) or adding them to the operational environment.
  • Most PaaS environments of today don’t even let you make use of these features, at any cost, because of  constraints imposed by PaaS providers for the sake of simplifying and streamlining their operations.
  • In the future, PaaS will not only make these available but available at a negligible incremental operational cost.
  • Even beyond that, PaaS will make available application services that are, in traditional settings, completely out of scope for the application programmer. Early examples include CDN, DNS and loab balancing services offered, for example, by Amazon. An application developer in most traditional data centers would have to jump through endless hoops if she wanted to control these services within the application. I believe that these network-related services are just the low hanging fruits and many more once-unthinkable infrastructure services will become programmable as part of the application.

PaaS will become less about “hosting” and more about offering application services. In other words, going back to the formula I proposed on Twitter:

Cloud = Hosting + SOA

IaaS is a lot more “hosting” than SOA, PaaS is a lot more “SOA” (application infrastructure services available via APIs) than “hosting”.

You can read the full article for more.

Comments Off on Everything is PaaSible

Filed under API, Application Mgmt, Articles, Cloud Computing, Everything, Manageability, Mgmt integration, Middleware, PaaS, Utility computing

September 18, 2011

DMTF publishes draft of Cloud API

Note to anyone who still cares about IaaS standards: the DMTF has published a work in progress.

There was a lot of interest in the topic in 2009 and 2010. Some heated debates took place during Cloud conferences and a few symposiums were organized to try to coordinate various standard efforts. The DMTF started an “incubator” on the topic. Many companies brought submissions to the table, in various levels of maturity: VMware, Fujitsu, HP, Telefonica, Oracle and RedHat. IBM and Microsoft might also have submitted something, I can’t remember for sure.

The DMTF has been chugging along. The incubator turned into a working group. Unfortunately (but unsurprisingly), it limited itself to the usual suspects (and not all the independent Cloud experts out there) and kept the process confidential. But this week it partially lifted the curtain by publishing two work-in-progress documents.

They can be found at http://dmtf.org/standards/cloud but if you read this after March 2012 they won’t be there anymore, as DMTF likes to “expire” its work-in-progress documents. The two docs are:

The first one is the interesting one, and the one you should read if you want to see where the DMTF is going. It’s a RESTful specification (at the cost of some contortions, e.g. section 4.2.1.3.1). It supports both JSON and XML (bad idea). It plans to use RelaxNG instead of XSD (good idea). And also CIM/MOF (not a joke, see the second document for proof). The specification is pretty ambitious (it covers not just lifecycle operations but also monitoring and events) and well written, especially for a work in progress (props to Gil Pilz).

I am surprised by how little reaction there has been to this publication considering how hotly debated the topic used to be. Why is that?

A cynic would attribute this to people having given up on DMTF providing a Cloud API that has any chance of wide adoption (the adjoining CIM document sure won’t help reassure DMTF skeptics).

To the contrary, an optimist will see this low-key publication as a sign that the passions have cooled, that the trusted providers of enterprise software are sitting at the same table and forging consensus, and that the industry is happy to defer to them.

More likely, I think people have, by now, enough Cloud experience to understand that standardizing IaaS APIs is a minor part of the problem of interoperability (not to mention the even harder goal of portability). The serialization and plumbing aspects don’t matter much, and if they do to you then there are some good libraries that provide mappings for your favorite language. What matters is the diversity of resources and services exposed by Cloud providers. Those choices strongly shape the design of your application, much more than the choice between JSON and XML for the control API. And nobody is, at the moment, in position to standardize these services.

So congrats to the DMTF Cloud Working Group for the milestone, and please get the API finalized. Hopefully it will at least achieve the goal of narrowing down the plumbing choices to three (AWS, OpenStack and DMTF). But that’s not going to solve the hard problem.

2 Comments

Filed under API, Application Mgmt, Automation, Cloud Computing, DMTF, Everything, IaaS, IT Systems Mgmt, Manageability, Mgmt integration, Modeling, Portability, Protocols, REST, Specs, Standards, Tech, Utility computing, Virtual appliance, Virtualization

August 11, 2011

Perspectives on Cloud.com acquisition

Interesting analysis (by Gartner’s Lydia Leong) on the acquisition of Cloud.com by Citrix (apparently for 100x revenues) and its position as a cheaper alternative for vCloud (at least until OpenStack Nova becomes stable).

Great read, even though that part:

“[Zygna] uses Cloud.com to provide Amazon-compatible (and thus Rightscale-compatible) infrastructure internally, letting it easily move workloads across their own infrastructure and Amazon’s.”

is a bit of a simplification.

While I’m at it, here’s another take on Cloud.com, this time from an OSS license perspective. Namely, the difference between building your business on GPL (like Eucalyptus) or Apache 2 (like the more community-driven open source projects such as OpenStack).

Towards the end, there’s also a nice nod to the Oracle Cloud API:

“DMTF has been receiving other submissions for an API standard. Oracle has made its submission public.  It is based on an earlier Sun proposal, and it is the best API we have yet seen. Furthermore, Oracle has identified a core subset to allow initial early adoption, as well as areas where vendors (including themselves and crucially VMware) may continue to extend to allow differentiation.”

Here’s more on the Oracle Cloud API, including an explanation of the “core/extension” split mentioned above.

 

Comments Off on Perspectives on Cloud.com acquisition

Filed under Cloud Computing, DMTF, Everything, Governance, Mgmt integration, Open source, OpenStack, Oracle, Specs, Standards, Utility computing, Virtualization, VMware

July 27, 2011

BSM with Oracle Enterprise Manager 11g

My colleagues Ashwin Karkala and Govinda Sambamurthy have written a book about modeling and managing business services using the current version of Enterprise Manager Grid Control (11g R1). Nobody would have been better qualified for this task since they built a lot of the features they describe. I acted as a technical reviewer for this book and very much enjoyed reading it in the process.

Whether you are a current EM user who wants to make sure you know and use the BSM features or someone just considering EM for that task, this is the book you want.

The full title is Oracle Enterprise Manager Grid Control 11g R1: Business Service Management.

As a bonus feature, and for a limited time only, if you purchase this book over the next 48 hours you get to follow the authors, @ashwinkarkala and @govindars on Twitter at no extra cost! A $2,000 value (at least).

Comments Off on BSM with Oracle Enterprise Manager 11g

Filed under Application Mgmt, Book review, BSM, Everything, IT Systems Mgmt, Mgmt integration, Modeling, Oracle, People

June 22, 2011

Yoga framework for REST-like partial resource access

A tweet by Stefan Tilkov brought Yoga to my attention, “a framework for supporting REST-like URI requests with field selectors”.

As the name suggests, “Yoga” lets you practice some contortions that would strain a run-of-the-mill REST programmer. Basically, you can use a request like

GET /teams/4234.json?selector=:(members:(id,name,birthday)

to retrieve the id, name and birthday of all members of a softball team, rather than having to retrieve the team roaster and then do a GET on each and every team member to retrieve their name and birthday (and lots of other information you don’t care about).

Where have I seen this before? That use case came up over and over again when we were using SOAP Web services for resource management. I have personally crafted support for it a few times. Using this blog to support my memory, here is the list of SOAP-related management efforts listed in the “post-mortem on the previous IT management revolution”:

WSMF, WS-Manageability, WSDM, OGSI, WSRF, WS-Management, WS-ResourceTransfer, WSRA, WS-ResourceCatalog, CMDBf

Each one of them supports this “partial access” use case: WS-Management has :

WSMF, WS-Manageability, WSDM, OGSI, WSRF, WS-Management, WS-ResourceTransfer, WSRA, WS-ResourceCatalog, CMDBf

Each one of them supports this “partial access” use case: WS-Management has SelectorSet, WSRF has ResourceProperties, CMDBf has ContentSelector, WSRA has Fragments, etc.

Years ago, I also created the XMLFrag SOAP header to attack a more general version of this problem. There may be something to salvage in all this for people willing to break REST orthodoxy (with the full knowledge of what they gain and what they loose).

I’m not being sarcastic when I ask “where have I seen this before”. The problem hasn’t gone away just because we failed to solve it in a pragmatic way with SOAP. If the industry is moving towards HTTP+JSON then we’ll need to solve it again on that ground and it’s no surprise if the solution looks similar.

I have a sense of what’s coming next. XPath-for-JSON-over-the-wire. See, getting individual properties is nice, but sometimes you want more. You want to select only the members of the team who are above 14 years old. Or you just want to count these members rather than retrieve specific information about them individually. Or you just want a list of all the cities they live in. Etc.

But even though we want this, I am not convinced (anymore) that we need it.

What I know we need is better support for graph queries. Kingsley Idehen once provided a good explanation of why that is and how SPARQL and XML query languages (or now JSON query languages) complement one another (wouldn’t that be a nice trifecta: RDF/OWL’s precise modeling, JSON’s friendly syntax and SPARQL’s graph support – but I digress).

Going back to partial resource access, the last feature is the biggie: a fine-grained mechanism to update resource properties. That one is extra-hard.

5 Comments

Filed under API, CMDBf, Everything, Graph query, IT Systems Mgmt, Manageability, Mgmt integration, Modeling, Protocols, Query, REST, SOAP, SOAP header, Specs, Standards, Web services, WS-Management, WS-ResourceCatalog, WS-ResourceTransfer, WS-Transfer, XMLFrag, XPath

June 6, 2011

Comments on “The Good, the Bad, and the Ugly of REST APIs”

A survivor of intimate contact with many Cloud APIs, George Reese shared his thoughts about the experience in a blog post titled “The Good, the Bad, and the Ugly of REST APIs“.

Here are the highlights of his verdict, with some comments.

“Supporting both JSON and XML [is good]”

I disagree: Two versions of a protocol is one too many (the post behind this link doesn’t specifically discuss the JSON/XML dichotomy but its logic applies to that situation, as Tim Bray pointed out in a comment).

“REST is good, SOAP is bad”

Not necessarily true for all integration projects, but in the context of Cloud APIs, I agree. As long as it’s “pragmatic REST”, not the kind that involves silly contortions to please the REST police.

“Meaningful error messages help a lot”

True and yet rarely done properly.

“Providing solid API documentation reduces my need for your help”

Goes without saying (for a good laugh, check out the commenter on George’s blog entry who wrote that “if you document an API, you API immediately ceases to have anything to do with REST” which I want to believe was meant as a joke but appears written in earnest).

“Map your API model to the way your data is consumed, not your data/object model”

Very important. This is a core part of Humble Architecture.

“Using OAuth authentication doesn’t map well for system-to-system interaction”

Agreed.

“Throttling is a terrible thing to do”

I don’t agree with that sweeping statement, but when George expands on this thought what he really seems to mean is more along the lines of “if you’re going to throttle, do it smartly and responsibly”, which I can’t disagree with.

“And while we’re at it, chatty APIs suck”

Yes. And one of the main causes of API chattiness is fear of angering the REST gods by violating the sacred ritual. Either ignore that fear or, if you can’t, hire an expensive REST consultant to rationalize a less-chatty design with some media-type black magic and REST-bless it.

Finally George ends by listing three “ugly” aspects of bad APIs (“returning HTML in your response body”, “failing to realize that a 4xx error means I messed up and a 5xx means you messed up” and “side-effects to 500 errors are evil”) which I agree on but I see those as a continuation of the earlier point about paying attention to the error messages you return (because that’s what the developers who invoke your API will be staring at most of the time, even if they represents only 0.01% of the messages you return).

What’s most interesting is what’s NOT in George’s list. No nit-picking about REST purity. That tells you something about what matters to implementers.

If I haven’t yet exhausted my quota of self-referential links, you can read REST in practice for IT and Cloud management for more on the topic.

7 Comments

Filed under API, Cloud Computing, Everything, Implementation, Manageability, Mgmt integration, Modeling, Protocols, REST, SOAP, Specs, Tech

March 7, 2011

Reading IBM’s proposed standard for Cloud Architecture

Did you enjoy the first version of IBM’s Cloud Computing Reference Architecture? Did you even get certified on it? Then rejoice, because there’s a new version. IBM  recently submitted the IBM Cloud Computing Reference Architecture 2.0 to The Open Group.

I’m a bit out of practice reading this kind of IBMese (let’s just say that The Open Group was the right place to submit it) but I would never let my readers down. So, even though these box-within-a-box-within-a-box diagrams (see section 2) give me flashbacks to the days of OGF and WSRF, I soldiered on.

I didn’t understand the goal of the document enough to give you a fair summary, but I can share some thoughts.

It starts by talking a lot about SOA. I initially thought this was to make the point that Glen Daniels articulated very well in this tweet:

Yup, correct SOA patterns (loose coupling, dyn refs, coarse interfaces…) are exactly what you need for cloud apps. You knew this.

But no. Rather than Glen’s astute remark, IBM’s point is one meta-level lower. It’s that “Cloud solutions are SOA solutions”. Which I have a harder time parsing. If you though “service” was overloaded before…

While some of the IBM authors are SOA experts, others apparently come from a Telco background so we get OSS/BSS analogies next.

By that point, I’ve learned that Cloud is like SOA except when it’s like Telco (but there’s probably another reference architecture somewhere that explains that Telco is SOA, so it all adds up).

One thing that chagrined me was that even though this document is very high-level it still manages to go down into implementatin technologies long enough to assert, wrongly, that virtualization is required for Cloud solutions. Another Cloud canard repeated here is the IaaS/PaaS/SaaS segmentation of the Cloud world, to which IBM adds a BPaaS (Business Process as a Service) layer for good measure (for my take on how Cloud relates to SOA, and how I dislike the IaaS/PaaS/SaaS pyramid, see this write-up of the presentation I gave at last year’s Cloud Connect, especially the 3rd picture).

It gets a lot better if you persevere to page 29, where the “Architecture Principles” finally get introduced (if had been asked to edit the paper, I would have only kept the last 6 pages). They are:

  1. Design for Cloud-scale Efficiencies: When realizing cloud characteristics such as elasticity, self-service access, and flexible sourcing, the cloud design is strictly oriented to high cloud scale efficiencies and short time-to-delivery/time-to-change. (“Efficiency Principle”)
  2. Support Lean Service Management: The Common Cloud Management Platform fosters lean and lightweight service management policies, processes, and technologies. (“Lightweightness Principle”)
  3. Identify and Leverage Commonalities: All commonalities are identified and leveraged in cloud service design. (“Economies-of-scale principle”)
  4. Define and Manage generically along the Lifecycle of Cloud Services: Be generic across I/P/S/BPaaS & provide ‘exploitation’ mechanism to support various cloud services using a shared, common management platform (“Genericity”).

Each principle gets a nickname, thanks to which IBM can refer to this list as the ELEG principles (Efficiency, Lightweightness, Economies-of-scale, Genericity). It also spells GLEE, but apparently that’s wasn’t the prefered sequence.

The first principle is hard to disagree with. The second also rings true, including its dings on ITIL (but the irony of IBM exhaulting “Lightweightness” is hard to ignore). The third and fourth principles (by that time I had lost too many brain cells to understand how they differ) really scared me. While I can understand the motivation, they elicited a vision of zombies in blue suits (presumably undead IBM Distinguish Engineers and Fellows) staggering towards me: “frameworks… we want frameworks…”.

There you go. If you want more information (and, more importantly, unbiased information) go read the Reference Architecture yourself. I am not involved in The Open Group, and I have no idea what it plans to do with it (and if it has received other submissions of the same type). Though I wouldn’t be surprised if I see, in 5 years, some panic sales rep asking an internal mailing list “The customer RPF asks for a mapping of our solution to the Open Group Cloud Reference Architecture and apparently IBM has 94 slides about it, what do I do? Has anyone heard about this Reference Architecture? This is urgent.”

Urgent things are long in the making.

1 Comment

Filed under Application Mgmt, Automation, Big picture, BPM, BSM, Business Process, Cloud Computing, Everything, Governance, IBM, IT Systems Mgmt, ITIL, Mgmt integration, Utility computing

February 27, 2011

CloudFormation in context

I’ve been very positive about AWS CloudFormation (both in tweet and blog form) since its announcement . I want to clarify that it’s not the technology that excites me. There’s nothing earth-shattering in it. CloudFormation only covers deployment and doesn’t help you with configuration, monitoring, diagnostic and ongoing lifecycle. It’s been done before (including probably a half-dozen times within IBM alone, I would guess). We’ve had much more powerful and flexible frameworks for a long time (I can’t even remember when SmartFrog first came out). And we’ve had frameworks with better tools (though history suggests that tools for CloudFormation are already in the works, not necessarily inside Amazon).

Here are some non-technical reasons why I tweeted that “I have a feeling that the AWS CloudFormation format might become an even more fundamental de-facto standard than the EC2 API” even before trying it out.

It’s simple to use. There are two main reasons for this (and the fact that it uses JSON rather than XML is not one of them):
– It only support a small set of features
– It “hard-codes” resource types (e.g. EC2, Beanstalk, RDS…) rather than focusing on an abstract and extensible mechanism

It combines a format and an API. You’d think it’s obvious that the two are complementary. What can you do with a format if you don’t have an API to exchange documents in that format? Well, turns out there are lots of free-floating model formats out there for which there is no defined API. And they are still wondering why they never saw any adoption.

It merges IaaS and PaaS. AWS has always defied the “IaaS vs. PaaS” view of the Cloud. By bridging both, CloudFormation is a great way to provide a smooth transition. I expect most of the early templates to be very EC2-centric (are as most AWS deployments) and over time to move to a pattern in which EC2 resources are just used for what doesn’t fit in more specialized containers).

It comes at the right time. It picks the low-hanging fruits of the AWS automation ecosystem. The evangelism and proof of concept for templatized deployments have already taken place.

It provides a natural grouping of the various AWS resources you are currently consuming. They are now part of an explicit deployment context.

It’s free (the resources provisioned are not free, of course, but the fact that they came out of a CloudFormation deployment doesn’t change the cost).

Comments Off on CloudFormation in context

Filed under Amazon, Application Mgmt, Automation, Cloud Computing, Everything, Mgmt integration, Modeling, PaaS, Specs, Utility computing

February 26, 2011

AWS CloudFormation is the iPhone of Cloud services

Expanding on tweet that I wrote soon after the announcement of AWS CloudFormation.

The iPhone unifies the GPS, phone, PDA, camera and camcorder. CloudFormation does the same for infrastructure services (VMs, volumes, network…) and some platform services (Beanstalk, RDS, SimpleDB, SQS, SNS…). You don’t think about whether you should grab a phone or a PDA, you grab an iPhone and start using the feature you need. It’s the default tool. Similarly with CloudFormation, you won’t start by thinking about what AWS service you want to use. Rather, you grab a CloudFormation template and modify it as needed. The template (or the template editor) is the default tool.

The iPhone doesn’t just group features that used to be provided by many devices. It also allows these features to collaborate. It’s not that you get a PDA and a phone side-by-side in one device. You can press the “call” button from the “PDA” feature. CloudFormation doesn’t just bundle deployments to various AWS services, it wires them together.

Anyone can write apps for the iPhone. Anyone can write apps that use CloudFormation.

There’s an App Store for iPhone apps. On the CloudFormation side, it will probably come soon (right now Amazon has made templates available on S3, but that’s not a real store). Amazon has developed example templates for a set of common applications, but expect application authors to take ownership of that task soon. They’ll consider it one of their deliverables. Right next to the “download” button you’ll start seeing a “deploy to AWS” button. Guess which one will eventually be used the most?

It’s Apple’s platform and your applications have to comply with their policy. AWS is not as much of a control freak as Apple and doesn’t have an upfront approval process, but it has its terms of service and they too can get you kicked out.

The iPhone is not a standard platform (though you may consider it a de-facto standard). Same for AWS CloudFormation.

There are alternatives to the iPhone that define themselves primarily as being more open than it, mainly Android. Same for AWS with OpenStack (which probably will soon have its CloudFormation equivalent).

The iPhone infiltrated itself into corporations at the ground level, even if the CIO initially saw no reason to look beyond BlackBerry for corporate needs. Same with AWS.

Any other parallel? Any fundamental difference I missed?

1 Comment

Filed under Amazon, Application Mgmt, Automation, Cloud Computing, Everything, Mgmt integration, Modeling, OpenStack, PaaS, Portability, Specs, Tech, Utility computing, Virtual appliance

January 26, 2011

The REST bubble

Just yesterday I was writing about how Cloud APIs are like military parades. To some extent, their REST rigor is a way to enforce implementation discipline. But a large part of it is mostly bling aimed at showing how strong (for an army) or smart (for an API) the people in charge are.

Case in point, APIs that have very simple requirements and yet make a big deal of the fact that they are perfectly RESTful.

Just today, I learned (via the ever-informative InfoQ) about the JBoss SteamCannon project (a PaaS wrapper for Java and Ruby apps that can deploy on different host infrastructures like EC2 and VirtualBox). The project looks very interesting, but the API doc made me shake my head.

The very first thing you read is three paragraphs telling you that the API is fully HATEOS (Hypermedia as the Engine of Application State) compliant (our URLs are opaque, you hear me, opaque!) and an invitation to go read Roy’s famous take-down of these other APIs that unduly call themselves RESTful even though they don’t give HATEOS any love.

So here I am, a developer trying to deploy my WAR file on SteamCannon and that’s the API document I find.

Instead of the REST finger-wagging, can I have a short overview of what functions your API offers? Or maybe an example of a request call and its response?

I don’t mean to pick on SteamCannon specifically, it just happens to be a new Cloud API that I discovered today (all the Cloud API out there also spend too much time telling you how RESTful they are and not enough time showing you how simple they are). But when an API document starts with a REST lesson and when PowerPoint-waving sales reps pitch “RESTful APIs” to executives you know this REST thing has gone way beyond anything related to “the fundamentals”.

We have a REST bubble on our hands.

Again, I am not criticizing REST itself. I am criticizing its religious and ostentatious application rather than its practical use based on actual requirements (this was my take on its practical aspects in the context of Cloud APIs).

14 Comments

Filed under API, Application Mgmt, Cloud Computing, Everything, JBoss, Mgmt integration, Protocols, REST, Utility computing

January 24, 2011

Cloud APIs are like military parades

The previous post (“Amazon proves that REST doesn’t matter for Cloud APIs”) attracted some interesting comments on the blog itself, on Hacker News and in a response post by Mike Pearce (where I assume the photo is supposed to represent me being an AWS fanboy). I failed to promptly follow-up on it and address the response, then the holidays came. But Mark Little was kind enough to pick the entry up for discussion on InfoQ yesterday which brought new readers and motivated me to write a follow-up.

Mark did a very good job at summarizing my point and he understood that I wasn’t talking about the value (or lack of value) of REST in general. Just about whether it is useful and important in the very narrow field of Cloud APIs. In that context at least, what seems to matter most is simplicity. And REST is not intrinsically simpler.

It isn’t a controversial statement in most places that RPC is easier than REST for developers performing simple tasks. But on the blogosphere I guess it needs to be argued.

Method calls is how normal developers write normal code. Doing it over the wire is the smallest change needed to invoke a remote API. The complexity with RPC has never been conceptual, it’s been in the plumbing. How do I serialize my method call and send it over? CORBA, RMI and SOAP tried to address that, none of them fully succeeded in keeping it simple and yet generic enough for the Internet. XML-RPC somehow (and unfortunately) got passed over in the process.

So what did AWS do? They pretty much solved that problem by using parameters in the URL as a dead-simple way to pass function parameters. And you get the response as an XML doc. In effect, it’s one-half of XML-RPC. Amazon did not invent this pattern. And the mechanism has some shortcomings. But it’s a pragmatic approach. You get the conceptual simplicity of RPC, without the need to agree on an RPC framework that tries to address way more than what you need. Good deal.

So, when Mike asks “Does the fact that AWS use their own implementation of an API instead of a standard like, oh, I don’t know, REST, frustrate developers who really don’t want to have to learn another method of communicating with AWS?” and goes on to answer “Yes”, I scratch my head. I’ve met many developers struggling to understand REST. I’ve never met a developer intimidated by RPC. As to the claim that REST is a “standard”, I’d like to read the spec. Please don’t point me to a PhD dissertation.

That being said, I am very aware that simplicity can come back to bite you, when it’s not just simple but simplistic and the task at hand demands more. Andrew Wahbe hit the nail on the head in a comment on my original post:

Exposing an API for a unique service offered by a single vendor is not going to get much benefit from being RESTful.

Revisit the issue when you are trying to get a single client to work across a wide range of cloud APIs offered by different vendors; I’m willing to bet that REST would help a lot there. If this never happens — the industry decides that a custom client for each Cloud API is sufficient (e.g. not enough offerings on the market, or whatever), then REST may never be needed.

Andrew has the right perspective. The usage patterns for Cloud APIs may evolve to the point where the benefits of following the rules of REST become compelling. I just don’t think we’re there and frankly I am not holding my breath. There are lots of functional improvements needed in Cloud services before the burning issue becomes one of orchestrating between Cloud providers. And while a shared RESTful API would be the easiest to orchestrate, a shared RPC API will still be very reasonably manageable. The issue will mostly be one of shared semantics more than protocol.

Mike’s second retort was that it was illogical for me to say that software developers are mostly isolated from REST because they use Cloud libraries. Aren’t these libraries written by developers? What about these, he asks. Well, one of them, Boto‘s Mitch Garnaat left a comment:

Good post. The vast majority of AWS (or any cloud provider’s) users never see the API. They interact through language libraries or via web-based client apps. So, the only people who really care are RESTafarians, and library developers (like me).

Perhaps it’s possible to have an API that’s so bad it prevents people from using it but the AWS Query API is no where near that bad. It’s fairly consistent and pretty easy to code to. It’s just not REST.

Yup. If REST is the goal, then this API doesn’t reach it. If usefulness is the goal, then it does just fine.

Mike’s third retort was to take issue with that statement I made:

The Rackspace people are technically right when they point out the benefits of their API compared to Amazon’s. But it’s a rounding error compared to the innovation, pragmatism and frequency of iteration that distinguishes the services provided by Amazon. It’s the content that matters.

Mike thinks that

If Rackspace are ‘technically’ right, then they’re right. There’s no gray area. Morally, they’re also right and mentally, physically and spiritually, they’re right.

Sure. They’re technically, mentally, physically and spiritually right. They may even be legally, ethically, metaphysically and scientifically right. Amazon is only practically right.

This is not a ding on Rackspace. They’ll have to compete with Amazon on service (and price), not on API, as they well know and as they are doing. But they are racing against a fast horse.

More generally, the debate about how much the technical merits of an API matters (beyond the point where it gets the job done) is a recurring one. I am talking as a recovering over-engineer.

In a post almost a year ago, James Watters declared that it matters. Mitch Garnaat weighed on the other side: “given how few people use the raw API we probably spend too much time worrying about details“, “maybe we worry too much about aesthetics“, “I still wonder whether we obsess over the details of the API’s a bit too much“ (in case you can’t tell, I’m a big fan of Mitch).

Speaking of people I admire, Shlomo Swidler (“in general, only library developers use the raw HTTP. Everyone else uses a library“) and Joe Arnold (“library integration (fog / jclouds / libcloud) is more important for new #IaaS providers than an API“) make the right point. Rather than spending hours obsessing about the finer points of your API, spend the time writing love letters to Mitch and Adrian so they support you in their libraries (also, allocate less of your design time to RESTfulness and more to the less glamorous subject of error handling).

OK, I’ll pile on two more expert testimonies. Righscale’s Thorsten von Eicken (“the API itself is more a programming exercise than a fundamental issue, it’s the semantics of the resources behind the API that really matter“) and F5’s Lori MacVittie (“the World Doesn’t Care About APIs“).

Bottom line, I see APIs a bit like military parades. Soldiers know better than to walk in tight formation, wearing bright colors and to the sound of fanfare into the battlefield. So why are parade exercises so prevalent in all armies? My guess is that they are used to impress potential enemies, reassure citizens and reflect on the strength of the country’s leaders. But military parades are also a way to ensure internal discipline. You may not need to use parade moves on the battlefield, but the fact that the unit is disciplined enough to perform them means they are also disciplined enough for the tasks that matter. Let’s focus on that angle for Cloud APIs. If your RPC API is consistent enough that its underlying model could be used as the basis for a REST API, you’re probably fine. You don’t need the drum rolls, stiff steps and the silly hats. And no need to salute either.

15 Comments

Filed under Amazon, API, Automation, Cloud Computing, Everything, IT Systems Mgmt, Mgmt integration, Protocols, REST, Specs, Utility computing

December 6, 2010

Amazon proves that REST doesn’t matter for Cloud APIs

Every time a new Cloud API is announced, its “RESTfulness” is heralded as if it was a MUST HAVE feature. And yet, the most successful of all Cloud APIs, the AWS API set, is not RESTful.

We are far enough down the road by now to conclude that this isn’t a fluke. It proves that REST doesn’t matter, at least for Cloud management APIs (there are web-scale applications of an entirely different class for which it does). By “doesn’t matter”, I don’t mean that it’s a bad choice. Just that it is not significantly different from reasonable alternatives, like RPC.

AWS mostly uses RPC over HTTP. You send HTTP GET requests, with instructions like ?Action=CreateKeyPair added in the URL. Or DeleteKeyPair. Same for any other resource (volume, snapshot, security group…). Amazon doesn’t pretend it’s RESTful, they just call it “Query API” (except for the DevPay API, where they call it “REST-Query” for unclear reasons).

Has this lack of REStfulness stopped anyone from using it? Has it limited the scale of systems deployed on AWS? Does it limit the flexibility of the Cloud offering and somehow force people to consume more resources than they need? Has it made the Amazon Cloud less secure? Has it restricted the scope of platforms and languages from which the API can be invoked? Does it require more experienced engineers than competing solutions?

I don’t see any sign that the answer is “yes” to any of these questions. Considering the scale of the service, it would be a multi-million dollars blunder if indeed one of them had a positive answer.

Here’s a rule of thumb. If most invocations of your API come via libraries for object-oriented languages that more or less map each HTTP request to a method call, it probably doesn’t matter very much how RESTful your API is.

The Rackspace people are technically right when they point out the benefits of their API compared to Amazon’s. But it’s a rounding error compared to the innovation, pragmatism and frequency of iteration that distinguishes the services provided by Amazon. It’s the content that matters.

If you think it’s rich, for someone who wrote a series of post examining “REST in practice for IT and Cloud management” (part 1, part 2 and part 3), to now declare that REST doesn’t matter, well go back to these posts. I explicitly set them up as an effort to investigate whether (and in what way) it mattered and made it clear that my intuition was that actual RESTfulness didn’t matter as much as simplicity. The AWS API being an example of the latter without the former. As I wrote in my review of the Sun Cloud API, “it’s not REST that matters, it’s the rest”. One and a half years later, I think the case is closed.

17 Comments

Filed under Amazon, Application Mgmt, Cloud Computing, Everything, Implementation, Mgmt integration, REST, Specs, Utility computing

November 3, 2010

Cloud management is to traditional IT management what spreadsheets are to calculators

It’s all in the title of the post. An elevator pitch short enough for a 1-story ride. A description for business people. People who don’t want to hear about models, virtualization, blueprints and devops. But people who also don’t want to be insulted with vague claims about “business/IT alignment” and “agility”.

The focus is on repeatability. Repeatability saves work and allows new approaches. I’ve found spreadsheets (and “super-spreadsheets”, i.e. more advanced BI tools) to be a good analogy for business people. Compared to analysts furiously operating calculators, spreadsheets save work and prevent errors. But beyond these cost savings, they allow you to do things you wouldn’t even try to do without them. It’s not just the same process, done faster and cheaper. It’s a more mature way of running your business.

Same with the “Cloud” style of IT management.

3 Comments

Filed under Application Mgmt, Automation, Big picture, Business, Cloud Computing, DevOps, Everything, IT Systems Mgmt, Manageability, Mgmt integration, Utility computing

October 19, 2010

Lifting the curtain on PaaS Cloud infrastructure (can you handle the truth?)

The promise of PaaS is that application owners don’t need to worry about the infrastructure that powers the application. They just provide application artifacts (e.g. WAR files) and everything else is taken care of. Backups. Scaling. Infrastructure patching. Network configuration. Geographic distribution. Etc. All these headaches are gone. Just pick from a menu of quality of service options (and the corresponding price list). Make your choice and forget about it.

In theory.

In practice no abstraction is leak-proof and the abstractions provided by PaaS environments are even more porous than average. The first goal of PaaS providers should be to shore them up, in order to deliver on the PaaS value proposition of simplification. But at some point you also have to acknowledge that there are some irreducible leaks and take pragmatic steps to help application administrators deal with them. The worst thing you can do is have application owners suffer from a leaky abstraction and refuse to even acknowledge it because it breaks your nice mental model.

Google App Engine (GAE) gives us a nice and simple example. When you first deploy an application on GAE, it is deployed as just one instance. As traffic increases, a second instance comes up to handle the load. Then a third. If traffic decreases, one instance may disappear. Or one of them may just go away for no reason (that you’re aware of).

It would be nice if you could deploy your application on what looks like a single, infinitely scalable, machine and not ever have to worry about horizontal scale-out. But that’s just not possible (at a reasonable cost) so Google doesn’t try particularly hard to hide the fact that many instances can be involved. You can choose to ignore that fact and your application will still work. But you’ll notice that some requests take a lot more time to complete than others (which is typically the case for the first request to hit a new instance). And some requests will find an empty local cache even though your application has had uninterrupted traffic. If you choose to live with the “one infinitely scalable machine” simplification, these are inexplicable and unpredictable events.

Last week, as part of the release of the GAE SDK 1.3.8, Google went one step further in acknowledging that several instances can serve your application, and helping you deal with it. They now give you a console (pictured below) which shows the instances currently serving your application.

I am very glad that they added this console, because it clearly puts on the table the question of how much your PaaS provider should open the kimono. What’s the right amount of visibility, somewhere between “one infinitely scalable computer” and giving you fan speeds and CPU temperature?

I don’t know what the answer is, but unfortunately I am pretty sure this console is not it. It is supposed to be useful “in debugging your application and also understanding its performance characteristics“. Hmm, how so exactly? Not only is this console very simple, it’s almost useless. Let me enumerate the ways.

Misleading

Actually it’s worse than useless, it’s misleading. As we can see on the screen shot, two of the instances saw no traffic during the collection period (which, BTW, we don’t know the length of), while the third one did all the work. At the top, we see an “average latency” value. Averaging latency across instances is meaningless if you don’t weight it properly. In this case, all the requests went to the instance that had an average latency of 1709ms, but apparently the overall average latency of the application is 569.7ms (yes, that’s 1709/3). Swell.

No instance identification

What happens when the console is refreshed? Maybe there will only be two instances. How do I know which one went away? Or say there are still three, how do I know these are the same three? For all I know it could be one old instance and two new ones. The single most important data point (from the application administrator’s perspective) is when a new instance comes up. I have no way, in this UI, to know reliably when that happens: no instance identification, no indication of the age of an instance.

Average memory

So we get the average memory per instance. What are we supposed to do with that information? What’s a good number, what’s a bad number? How much memory is available? Is my app memory-bound, CPU-bound or IO-bound on this instance?

Configuration management

As I have described before, change and configuration management in a PaaS setting is a thorny problem. This console doesn’t tackle it. Nowhere does it say which version of the GAE platform each instance is running. Google announces GAE SDK releases (the bits you download), but these releases are mostly made of new platform features, so they imply a corresponding update to Google’s servers. That can’t happen instantly, there must be some kind of roll-out (whether the instances can be hot-patched or need to be recycled). Which means that the instances of my application are transitioned from one platform version to another (and presumably that at a given point in time all the instances of my application may not be using the same platform version). Maybe that’s the source of my problem. Wouldn’t it be nice if I knew which platform version an instance runs? Wouldn’t it be nice if my log files included that? Wouldn’t it be nice if I could request an app to run on a specific platform version for debugging purpose? Sure, in theory all the upgrades are backward-compatible, so it “shouldn’t matter”. But as explained above, “the worst thing you can do is have application owners suffer from a leaky abstraction and refuse to even acknowledge it“.

OK, so the instance monitoring console Google just rolled out is seriously lacking. As is too often the case with IT monitoring systems, it reports what is convenient to collect, not what is useful. I’m sure they’ll fix it over time. What this console does well (and really the main point of this blog) is illustrate the challenge of how much information about the underlying infrastructure should be surfaced.

Surface too little and you leave application administrators powerless. Surface more data but no control and you’ll leave them frustrated. Surface some controls (e.g. a way to configure the scaling out strategy) and you’ve taken away some of the PaaS simplicity and also added constraints to your infrastructure management strategy, making it potentially less efficient. If you go down that route, you can end up with the other flavor of PaaS, the IaaS-based PaaS in which you have an automated way to create a deployment but what you hand back to the application administrator is a set of VMs to manage.

That IaaS-centric PaaS is a well-understood beast, to which many existing tools and management practices can be applied. The “pure PaaS” approach pioneered by GAE is much more of a terra incognita from a management perspective. I don’t know, for example, whether exposing the platform version of each instance, as described above, is a good idea. How leaky is the “platform upgrades are always backward-compatible” assumption? Google, and others, are experimenting with the right abstraction level, APIs, tools, and processes to expose to application administrators. That’s how we’ll find out.

1 Comment

Filed under Application Mgmt, Automation, Cloud Computing, Everything, Google App Engine, IT Systems Mgmt, Manageability, Mgmt integration, Middleware, PaaS, Utility computing

October 14, 2010

Redeeming the service description document

A bicycle is a convenient way to go buy cigarettes. Until one day you realize that buying cigarettes is a bad idea. At which point you throw away your bicycle.

Sounds illogical? Well, that’s pretty much what the industry has done with service descriptions. It went this way: people used WSDL (and stub generation tools built around it) to build distributed applications that shared too much. Some people eventually realized that was a bad approach. So they threw out the whole idea of a service description. And now, in the age of APIs, we are no more advanced than we were 15 years ago in terms of documenting application contracts. It’s tragic.

The main fallacies involved in this stagnation are:

  • Assuming that service descriptions are meant to auto-generate all-encompassing program stubs,
  • Looking for the One True Description for a given service,
  • Automatically validating messages based on the service description.

I’ll leave the first one aside, it’s been widely covered. Let’s drill in a bit into the other two.

There is NOT One True Description for a given service

Many years ago, in the same galaxy where we live today (only a few miles from here, actually), was a development team which had to implement a web service for a specific WSDL. They fed the WSDL to their SOAP stack. This was back in the days when WSDL interoperability was a “promise” in the “political campaign” sense of the term so of course it didn’t work. As a result, they gave up on their SOAP stack and implemented the service as a servlet. Which, for a team new to XML, meant a long delay and countless bugs. I’ll always remember the look on the dev lead’s face when I showed him how 2 minutes and a text editor were all you needed to turn the offending WSDL in to a completely equivalent WSDL (from the point of view of on-the-wire messages) that their toolkit would accept.

(I forgot what the exact issue was, maybe having operations with different exchange patterns within the same PortType; or maybe it used an XSD construct not supported by the toolkit, and it was just a matter of removing this constraint and moving it from schema to code. In any case something that could easily be changed by editing the WSDL and the consumer of the service wouldn’t need to know anything about it.)

A service description is not the literal word of God. That’s true no matter where you get it from (unless it’s hand-delivered by an angel, I guess). Just because adding “?wsdl” to the URL of a Web service returns an XML document doesn’t mean it’s The One True Description for that service. It’s just the most convenient one to generate for the app server on which the service is deployed.

One of the things that most hurts XML as an on-the-wire format is XSD. But not in the sense that “XSD is bad”. Sure, it has plenty of warts, but what really hurts XML is not XSD per se as much as the all-too-common assumption that if you use XML you need to have an XSD for it (see fat-bottomed specs, the key message of which I believe is still true even though SML and SML-IF are now dead).

I’ve had several conversations like this one:

– The best part about using JSON and REST was that we didn’t have to deal with XSD.
– So what do you use as your service contract?
– Nothing. Just a human-readable wiki page.
– If you don’t need a service contract, why did you feel like you had to write an XSD when you were doing XML? Why not have a similar wiki page describing the XML format?
– …

It’s perfectly fine to have service descriptions that are optimized to meet a specific need rather than automatically focusing on syntax validation. Not all consumers of a service contract need to be using the same description. It’s ok to have different service descriptions for different users and/or purposes. Which takes us to the next fallacy. What are service descriptions for if not syntax validation?

A service description does NOT mean you have to validate messages

As helpful as “validation” may seem as a concept, it often boils down to rejecting messages that could otherwise be successfully processed. Which doesn’t sound quite as useful, does it?

There are many other ways in which service descriptions could be useful, but they have been largely neglected because of the focus on syntactic validation and stub generation. Leaving aside development use cases and looking at my area of focus (application management), here are a few use cases for service descriptions:

Creating test messages (aka “synthetic transactions”)

A common practice in application management is to send test messages at regular intervals (often from various locations, e.g. branch offices) to measure the availability and response time of an application from the consumer’s perspective. If a WSDL is available for the service, we use this to generate the skeleton of the test message, and let the admin fill in appropriate values. Rather than a WSDL we’d much rather have a “ready-to-use” (possibly after admin review) test message that would be provided as part of the service description. Especially as it would be defined by the application creator, who presumably knows a lot more about that makes a safe and yet relevant message to send to the application as a ping.

Attaching policies and SLAs

One of the things that WSDLs are often used for, beyond syntax validation and stub generation, is to attach policies and SLAs. For that purpose, you really don’t need the XSD message definition that makes up so much of the WSDL. You really just need a way to identify operations on which to attach policies and SLAs. We could use a much simpler description language than WSDL for this. But if you throw away the very notion of a description language, you’ve thrown away the baby (a classification of the requests processed by the service) along with the bathwater (a syntax validation mechanism).

Governance / versioning

One benefit of having a service description document is that you can see when it changes. Even if you reduce this to a simple binary value (did it change since I last checked, y/n) there’s value in this. Even better if you can introspect the description document to see which requests are affected by the change. And whether the change is backward-compatible. Offering the “before” XSD and the “after” XSD is almost useless for automatic processing. It’s unlikely that some automated XSD inspection can tell me whether I can keep using my previous messages or I need to update them. A simple machine-readable declaration of that fact would be a lot more useful.

I just listed three, but there are other application management use cases, like governance/auditing, that need a service description.

In the SOAP world, we usually make do with WSDL for these tasks, not because it’s the best tool (all we really need is a way to classify requests in “buckets” – call them “operations” if you want – based on the content of the message) but because WSDL is the only understanding that is shared between the caller and the application.

By now some of you may have already drafted in your head the comment you are going to post explaining why this is not a problem if people just use REST. And it’s true that with REST there is a default categorization of incoming messages. A simple matrix with the various verbs as columns (GET, POST…) and the various resource types as rows. Each message can be unambiguously placed in one cell of this matrix, so I don’t need a service description document to have a request classification on which I can attach SLAs and policies. Granted, but keep these three things in mind:

  • This default categorization by verb and resource type can be a quite granular. Typically you wouldn’t have that many different policies on your application. So someone who understands the application still needs to group the invocations into message categories at the right level of granularity.
  • This matrix is only meaningful for the subset of “RESTful” apps that are truly… RESTful. Not for all the apps that use REST where it’s an easy mental mapping but then define resource types called “operations” or “actions” that are just a REST veneer over RPC.
  • Even if using REST was a silver bullet that eliminated the need for service definitions, as an application management vendor I don’t get to pick the applications I manage. I have to have a solution for what customers actually do. If I restricted myself to only managing RESTful applications, I’d shrink my addressable market by a few orders of magnitude. I don’t have an MBA, but it sounds like a bad idea.

This is not a SOAP versus REST post. This is not a XML versus JSON post. This is not a WSDL versus WADL post. This is just a post lamenting the fact that the industry seems to have either boxed service definitions into a very limited use case, or given up on them altogether. It I wasn’t recovering from standards burnout, I’d look into a versatile mechanism for describing application services in a way that is geared towards message classification more than validation.

Comments Off on Redeeming the service description document

Filed under API, Application Mgmt, Everything, Governance, IT Systems Mgmt, Manageability, Mashup, Mgmt integration, Middleware, Modeling, Protocols, REST, SML, SOA, Specs, Standards

September 12, 2010

The PaaS Lament: In the Cloud, application administrators should administrate applications

Some organizations just have “systems administrators” in charges of their applications. Others call out an “application administrator” role but it is usually overloaded: it doesn’t separate the application platform administrator from the true application administrator. The first one is in charge of the application runtime infrastructure (e.g. the application server, SOA tools, MDM, IdM, message bus, etc). The second is in charge of the applications themselves (e.g. Java applications and the various artifacts that are used to customize the middleware stack to serve the application).

In effect, I am describing something close to the split between the DBA and the application administrators. The first step is to turn this duo (app admin, DBA) into a triplet (app admin, platform admin, DBA). That would be progress, but such a triplet is not actually what I am really after as it is too strongly tied to a traditional 3-tier architecture. What we really need is a first-order separation between the application administrator and the infrastructure administrators (not the plural). And then, if needed, a second-order split between a handful of different infrastructure administrators, one of which may be a DBA (or a DBA++, having expanded to all data storage services, not just relational), another of which may be an application platform administrator.

There are two reasons for the current unfortunate amalgam of the “application administrator” and “application platform administrator” roles. A bad one and a good one.

The bad reason is a shortcomings of the majority of middleware products. While they generally do a good job on performance, reliability and developer productivity, they generally do a poor job at providing a clean separation of the performance/administration functions that are relevant to the runtime and those that are relevant to the deployed applications. Their usual role definitions are more structured along the lines of what actions you can perform rather than on what entities you can perform them. From a runtime perspective, the applications are not well isolated from one another either, which means that in real life you have to consider the entire system (the middleware and all deployed applications) if you want to make changes in a safe way.

The good reason for the current lack of separation between application administrators and middleware administrators is that middleware products have generally done a good job of supporting development innovation and optimization. Frameworks appear and evolve to respond to the challenges encountered by developers. Knobs and dials are exposed which allow heavy customization of the runtime to meet the performance and feature needs of a specific application. With developers driving what middleware is used and how it is used, it’s a natural consequence that the middleware is managed in tight correlation with how the application is managed.

Just like there is tension between DBAs and the “application people” (application administrators and/or developers), there is an inherent tension in the split I am advocating between application management and application platform management. The tension flows from the previous paragraph (the “good reason” for the current amalgam): a split between application administrators and application platform administrators would have the downside of dampening application platform innovation. Or rather it redirects it, in a mutation not unlike the move from artisans to industry. Rather than focusing on highly-specialized frameworks and highly-tuned runtimes, the application platform innovation is redirected towards the goals of extreme cost efficiency, high reliability, consistent security and scalability-by-default. These become the main objectives of the application platform administrator. In that perspective, the focus of the application architect and the application administrator needs to switch from taking advantage of the customizability of the runtime to optimize local-node performance towards taking advantage of the dynamism of the application platform to optimize for scalability and economy.

Innovation in terms of new frameworks and programming models takes a hit in that model, but there are ways to compensate. The services offered by the platform can be at different levels of generality. The more generic ones can be used to host innovative application frameworks and tools. For example, a highly-specialized service like an identity management system is hard to use for another purpose, but on the other hand a JVM can be used to host not just business applications but also platform-like things like Hadoop. They can run in the “application space” until they are mature enough to be incorporated in the “application platform space” and become the responsibility of the application platform administrator.

The need to keep a door open for innovation is part of why, as much as I believe in PaaS, I don’t think IaaS is going away anytime soon. Not only do we need VMs for backward-looking legacy apps, we also need polyvalent platforms, like a VM, for forward-looking purposes, to allow developers to influence platform innovation, based on their needs and ideas.

Forget the guillotine, maybe I should carry an axe around. That may help get the point across, that I want to slice application administrators in two, head to toe. PaaS is not a question of runtime. It’s a question of administrative roles.

Comments Off on The PaaS Lament: In the Cloud, application administrators should administrate applications

Filed under Application Mgmt, Cloud Computing, Everything, IT Systems Mgmt, Manageability, Mgmt integration, Middleware, PaaS, Utility computing, Virtualization

August 18, 2010

The necessity of PaaS: Will Microsoft be the Singapore of Cloud Computing?

From ancient Mesopotamia to, more recently, Holland, Switzerland, Japan, Singapore and Korea, the success of many societies has been in part credited to their lack of natural resources. The theory being that it motivated them to rely on human capital, commerce and innovation rather than resource extraction. This approach eventually put them ahead of their better-endowed neighbors.

A similar dynamic may well propel Microsoft ahead in PaaS (Platform as a Service): IaaS with Windows is so painful that it may force Microsoft to focus on PaaS. The motivation is strong to “go up the stack” when the alternative is to cultivate the arid land of Windows-based IaaS.

I should disclose that I work for one of Microsoft’s main competitors, Oracle (though this blog only represents personal opinions), and that I am not an expert Windows system administrator. But I have enough experience to have seen some of the many reasons why Windows feels like a much less IaaS-friendly environment than Linux: e.g. the lack of SSH, the cumbersomeness of RDP, the constraints of the Windows license enforcement system, the Windows update mechanism, the immaturity of scripting, the difficulty of managing Windows from non-Windows machines (despite WS-Management), etc. For a simple illustration, go to EC2 and compare, between a Windows AMI and a Linux AMI, the steps (and time) needed to get from selecting an image to the point where you’re logged in and in control of a VM. And if you think that’s bad, things get even worse when we’re not just talking about a few long-lived Windows server instances in the Cloud but a highly dynamic environment in which all steps have to be automated and repeatable.

I am not saying that there aren’t ways around all this, just like it’s not impossible to grow grapes in Holland. It’s just usually not worth the effort. This recent post by RighScale illustrates both how hard it is but also that it is possible if you’re determined. The question is what benefits you get from Windows guests in IaaS and whether they justify the extra work. And also the additional license fee (while many of the issues are technical, others stem more from Microsoft’s refusal to acknowledge that the OS is a commodity). [Side note: this discussion is about Windows as a guest OS and not about the comparative virtues of Hyper-V, Xen-based hypervisors and VMWare.]

Under the DSI banner, Microsoft has been working for a while on improving the management/automation infrastructure for Windows, with tools like PowerShell (which I like a lot). These efforts pre-date the Cloud wave but definitely help Windows try to hold it own on the IaaS battleground. Still, it’s an uphill battle compared with Linux. So it makes perfect sense for Microsoft to move the battle to PaaS.

Just like commerce and innovation will, in the long term, bring more prosperity than focusing on mining and agriculture, PaaS will, in the long term, yield more benefits than IaaS. Even though it’s harder at first. That’s the good news for Microsoft.

On the other hand, lack of natural resources is not a guarantee of success either (as many poor desertic countries can testify) and Microsoft will have to fight to be successful in PaaS. But the work on Azure and many research efforts, like the “next-generation programming model for the cloud” (codename “Orleans”) that Mary Jo Foley revealed today, indicate that they are taking it very seriously. Their approach is not restricted by a VM-centric vision, which is often tempting for hypervisor and OS vendors. Microsoft’s move to PaaS is also facilitated by the fact that, while system administration and automation may not be a strength, development tools and application platforms are.

The forward-compatible Cloud will soon overshadow the backward-compatible Cloud and I expect Microsoft to play a role in it. They have to.

10 Comments

Filed under Application Mgmt, Automation, Azure, Cloud Computing, DevOps, Everything, IT Systems Mgmt, Linux, Manageability, Mgmt integration, Microsoft, Middleware, Oslo, PaaS, Research, Utility computing, WS-Management

August 5, 2010

Updates on Microsoft Oslo and “SSH on Windows”

I’ve been tracking the modeling technology previously known as “Microsoft Oslo” with a sympathetic eye for the almost three years since it’s been introduced. I look at it from the perspective of model-driven IT management but the news hadn’t been good on that front lately (except for Douglas Purdy’s encouraging hint).

The prospects got even bleaker today, at least according to the usually-well-informed Mary Jo Foley, who writes: “Multiple contacts of mine are telling me that Microsoft has decided to shelve Quadrant and ‘refocus’ M.” Is “M” the end of the SDM/SML/M model-driven management approach at Microsoft? Or is the “refocus” a hint that M is returning “home” to address IT management use cases? Time (or Doug) will tell…

While we’re talking about Microsoft and IT automation, I have one piece of free advice for the Microsofties: people *really* want to SSH into Windows servers. Here’s how I know. This blog rarely talks about Microsoft but over the course of two successive weekends over a year ago I toyed with ways to remotely manage Windows machines using publicly documented protocols. In effect, showing what to send on the wire (from Linux or any platform) to leverage the SOAP-based management capabilities in recent versions of Windows. To my surprise, these posts (1, 2, 3) still draw a disproportionate amount of traffic. And whenever I look at my httpd logs, I can count on seeing search engine queries related to “windows native ssh” or similar keywords.

If heterogeneous Cloud is something Microsoft cares about they need to better leverage the potential of the PowerShell Remoting Protocol. They can release open-source Python, Java and Ruby client-side libraries. Alternatively, they can drastically simplify the protocol, rather than its current “binary over SOAP” (you read this right) incarnation. Because the poor Kridek who is looking for the “WSDL for WinRM / Remote Powershell” is in for a nasty surprise if he finds it and thinks he’ll get a ready-to-use stub out of it.

That being said, a brave developer willing to suck it up and create such a Python/Ruby/Java library would probably make some people very grateful.

3 Comments

Filed under Application Mgmt, Automation, Everything, Implementation, IT Systems Mgmt, Manageability, Mgmt integration, Microsoft, Modeling, Oslo, Protocols, SML, SOAP, Specs, Tech, WS-Management

July 18, 2010

Introducing the Oracle Cloud API

Oracle recently published a Cloud management API on OTN and also submitted a subset of the API to the new DMTF Cloud Management working group. The OTN specification, titled “Oracle Cloud Resource Model API”, is available here. In typical DMTF fashion, the DMTF-submitted specification is not publicly available (if you have a DMTF account and are a member of the right group you can find it here). It is titled the “Oracle Cloud Elemental Resource Model” and is essentially the same as the OTN version, minus sections 9.2, 9.4, 9.6, 9.8, 9.9 and 9.10 (I’ll explain below why these sections have been removed from the DMTF submission). Here is also a slideset that was recently used to present the submitted specification at a DMTF meeting.

So why two documents? Because they serve different purposes. The Elemental Resource Model, submitted to DMTF, represents the technical foundation for the IaaS layer. It’s not all of IaaS, just its core. You can think of its scope as that of the base EC2 service (boot a VM from an image, attach a volume, connect to a network). It’s the part that appears in all the various IaaS APIs out there, and that looks very similar, in its model, across all of them. It’s the part that’s ripe for a simple standard, hopefully free of much of the drama of a more open-ended and speculative effort. A standard that can come out quickly and provide interoperability right out of the gate (for the simple use cases it supports), not after years of plugfests and profiles. This is the narrow scope I described in an earlier rant about Cloud standards:

I understand the pain of customers today who just want to have a bit more flexibility and portability within the limited scope of the VM/Volume/IP offering. If we really want to do a standard today, fine. Let’s do a very small and pragmatic standard that addresses this. Just a subset of the EC2 API. Don’t attempt to standardize the virtual disk format. Don’t worry about application-level features inside the VM. Don’t sweat the REST or SOA purity aspects of the interface too much either. Don’t stress about scalability of the management API and batching of actions. Just make it simple and provide a reference implementation. A few HTTP messages to provision, attach, update and delete VMs, volumes and IPs. That would be fine. Anything else (and more is indeed needed) would be vendor extensions for now.

Of course IaaS goes beyond the scope of the Elemental Resource Model. We’ll need load balancing. We’ll need tunneling to the private datacenter. We’ll need low-latency sub-networks. We’ll need the ability to map multi-tier applications to different security zones. Etc. Some Cloud platforms support some of these (e.g. Amazon has an answer to all but the last one), but there is a lot more divergence (both in the “what” and the “how”) between the various Cloud APIs on this. That part of IaaS is not ready for standardization.

Then there are the extensions that attempt to make the IaaS APIs more application-aware. These too exist in some Cloud APIs (e.g. vCloud vApp) but not others. They haven’t naturally converged between implementations. They haven’t seen nearly as much usage in the industry as the base IaaS features. It would be a mistake to overreach in the initial phase of IaaS standardization and try to tackle these questions. It would not just delay the availability of a standard for the base IaaS use cases, it would put its emergence and adoption in jeopardy.

This is why Oracle withheld these application-aware aspects from the DMTF submission, though we are sharing them in the specification published on OTN. We want to expose them and get feedback. We’re open to collaborating on them, maybe even in the scope of a standard group if that’s the best way to ensure an open IP framework for the work. But it shouldn’t make the upcoming DMTF IaaS specification more complex and speculative than it needs to be, so we are keeping them as separate extensions. Not to mention that DMTF as an organization has a lot more infrastructure expertise than middleware and application expertise.

Again, the “Elemental Resource Model” specification submitted to DMTF is the same as the “Oracle Cloud Resource Model API” on OTN except that it has a different license (a license grant to DMTF instead of the usual OTN license) and is missing some resources in the list of resource types (section 9).

Both specifications share the exact same protocol aspects. It’s pretty cleanly RESTful and uses a JSON serialization. The credit for the nice RESTful protocol goes to the folks who created the original Sun Cloud API as this is pretty much what the Oracle Cloud API adopted in its entirety. Tim Bray described the genesis and design philosophy of the Sun Cloud API last year. He also described his role and explained that “most of the heavy lifting was done by Craig McClanahan with guidance from Lew Tucker“. It’s a shame that the Oracle specification fails to credit the Sun team and I kick myself for not noticing this in my reviews. This heritage was noted from the get go in the slides and is, in my mind, a selling point for the specification. When I reviewed the main Cloud APIs available last summer (the first part in a “REST in practice for IT and Cloud management” series), I liked Sun’s protocol design the best.

The resource model, while still based on the Sun Cloud API, has seen many more changes. That’s where our tireless editor, Jack Yu, with help from Mark Carlson, has spent most of the countless hours he devoted to the specification. I won’t do a point to point comparison of the Sun model and the Oracle model, but in general most of the changes and additions are motivated by use cases that are more heavily tilted towards private clouds and compatibility with existing application infrastructure. For example, the semantics of a Zone have been relaxed to allow a private Cloud administrator to choose how to partition the Cloud (by location is an obvious option, but it could also by security zone or by organizational ownership, as heretic as this may sound to Cloud purists).

The most important differences between the DMTF and OTN versions relate to the support for assemblies, which are groups of VMs that jointly participate in the delivery of a composite application. This goes hand-in-hand with the recently-released Oracle Virtual Assembly Builder, a framework for creating, packing, deploying and configuring multi-tier applications. To support this approach, the Cloud Resource Model (but not the Elemental Model, as explained above) adds resource types such as AssemblyTemplate, AssemblyInstance and ScalabilityGroup.

So what now? The DMTF working group has received a large number of IaaS APIs as submissions (though not the one that matters most or the one that may well soon matter a lot too). If all goes well it will succeed in delivering a simple and useful standard for the base IaaS use cases, and we’ll be down to a somewhat manageable triplet (EC2, RackSpace/OpenStack and DMTF) of IaaS specifications. If not (either because the DMTF group tries to bite too much or because it succumbs to infighting) then DMTF will be out of the game entirely and it will be between EC2, OpenStack and a bunch of private specifications. It will be the reign of toolkits/library/brokers and hell on earth for all those who think that such a bridging approach is as good as a standard. And for this reason it will have to coalesce at some point.

As far as the more application-centric approach to hypervisor-based Cloud, well, the interesting things are really just starting. Let’s experiment. And let’s talk.

6 Comments

Filed under Amazon, API, Application Mgmt, Cloud Computing, DMTF, Everything, IT Systems Mgmt, Mgmt integration, Modeling, OpenStack, Oracle, Portability, Protocols, Specs, Standards, Utility computing, Virtual appliance, Virtualization