Category Archives: WS-Management

WS-Transfer, WS-ResourceTransfer, WS-Enumeration and WS-MetadataExchange on their way to W3C

A bit over a month ago, I mentioned my hope that WS-ResourceTransfer (WS-RT) would be allowed to rest in peace. This is apparently not to be and the specification is now on its way to W3C, along with WS-Transfer, WS-MetadataExchange and WS-Enumeration. This is not all that surprising and I had even hazarded a guess of who would join IBM in doing this. My list was IBM, CA, Fujitsu and Cisco. I got three out of four right, but Oracle replaced Cisco. The fact that the company I got wrong happens to be my employer is something I can’t really comment on, other than acknowledging the irony…

This is a very important development in the area of management standards. Some of the specifications listed here are used by WS-Management. They are also clearly intended to replace the WS-ResourceFramework stack that underpins WSDM. This is especially true of WS-RT which almost directly overlaps with WS-ResourceProperties. Users of both WS-Management and WSDM will take notice. As will those who have been standing on the side, waiting for things to stabilize…

If you are trying to relate this announcement to the WS-Management/WSDM convergence previously going on between Microsoft, IBM, HP and Intel (which is the forum in which WS-RT was originally produced), it looks like this is what the “convergence” has turned into. Except that three of the four vendors seem to have dropped out, thus my quotation marks around the word “convergence”.

The applicability of these specifications outside of the management domain seems to be assumed in this submission. It’s been often asserted but, in my mind, not yet proven. I don’t see the use of WS-RT by WS-Federation as a proof of this relevance (one of these days I’ll write a post to explain why).

It will be interesting to see how the W3C responds to this offer. The expected retort didn’t take long. If WS-RT wasn’t allowed to rest in peace, it won’t be allowed to REST in peace either. You can expect the blogosphere to light up with “WS-Transfer for RESTful applications” discussions (mostly making fun of WS-Transfer’s HTTP envy) very soon. Even though that’s just one of the many angles from which you can view this development, and not the most interesting one.

[UPDATED 2008/7/6: It took a little longer than expected, but the snarky/ironic blog posts have started: Steve, Mark, Tim, Bill, Stefan]


Filed under Everything, IT Systems Mgmt, Mgmt integration, SOAP, Specs, Standards, W3C, WS-Management, WS-ResourceTransfer, WS-Transfer

Recent IT management announcements

There were a few announcements relevant to the evolution of IT management over the last week. The most interesting is VMware’s release of the open-source (BSD license) VI SDK, a Java API to manage a host system and the virtual machines that run on it. Interesting that they went the way of a language-specific API. The alternatives, to complement/improve their existing web services SDK, would have been: define CIM classes and implement a WBEM provider (using CIM-HTTP and/or WS-Management), use WS-Management but without the CIM part (define the model as native XML, not XML-from-CIM), use a RESTful HTTP-driven interface to that same native XML model or, on the more sci-fi side, go the MDA way with a controller from which you retrieve the observed state and to which you specify the desired state. The Java API approach is the easiest one for developers to use, as long as they can access the Java ecosystem and they are mainly concerned with controlling the VMWare entities. If the management application also deals with many other resources (like the OS that runs in the guest machines or the hardware under the host, both of which are likely to have CIM models), a more model-centric approach could be more handy. The Java API of course has an underlying model (described here), but the interface itself is not model-centric. So what with all the DMTF-love that VMWare has been displaying lately (OVF submission, board membership, hiring of the DMTF president…). Should we expect a more model-friendly version of this API in the future? How does this relate to the DMTF SVPC working group that recently released some preliminary profiles? The choice to focus on beefing-up the Java-centric management story (which includes Jython, as VMWare was quick to point out) rather than the platform-agnostic, on-the-wire-interop side might be seen by the more twisted minds as a way to not facilitate Microsoft’s “manage VMWare today to replace it tomorrow” plan any more than necessary.

Speaking of Microsoft, in unrelated news we also got a heartbeat from them on the Oslo project: a tech preview of some of the components is scheduled for October. When Oslo was announced, there was a mix of “next gen BizTalk” aspects and “developer-driven DSI” aspects. From this report, the BizTalk part seems to be dominating. No word on use of SML.

And finally, SOA Software (who was previously called Digital Evolution and who acquired Blue Titan, Flamenco and LogicLibrary, in case you’re trying to keep track) has released a “SOA Development Governance Product”. Nothing too exciting from what I can see on InfoQ about it, but that’s a pretty superficial evaluation so don’t let me stop you. Am I the only one who twitches whenever “federation” is used to mean at worst “import” or at best “synchronization”? Did CMDBf start that trend? BTW, is it just an impression or did SOA Software give InfoQ a list of the questions they wanted to be asked?


Filed under DMTF, Everything, IT Systems Mgmt, Manageability, Mgmt integration, Open source, Oslo, OVF, SML, Standards, Tech, Virtualization, VMware, WS-Management

RESTful JMX access from someone who knows both sides

Anyone interested in application manageability and/or management integration should read about Jean-Francois Denise’s prototype for RESTful Access to JMX Instrumentation. Not (at least for now) as something to make use of, but to force us to think pragmatically about the pros and cons of the WS-* stack when used for management integration.

The interesting question is: which of these two interfaces (the WS-Management-based interface being standardized or the HTTP-centric interface that Jean-Francois prototyped) makes it easier to write a cross-platform management application such as the poker-cheating demo at JavaOne 2008?

Some may say that he cheated in that demo by using the Microsoft-provided WinRM implementation of WS-Management on the VBScript side. Without it, it would have clearly been a lot harder to implement the WS-Management based protocol in VBScript than the REST approach. True, but that’s the exact point of standards, that they allow such libraries to be made available to assist implementers. The question is whether such a library is available for your platform/language, how good and interoperable that library is (it could actually hinder rather than help) and what is the cost to the project of depending on it. Which is why the question is hard to answer in absolute. I suspect that, even with WinRM, the simple use case demonstrated at JavaOne would have been easier to implement using straight HTTP but that things change quickly when you run into more demanding use cases (e.g. event notification with filters, sequencing of large responses into an enumeration…). Which is why I still think that the sweetspot would be a simplified WS-Management specification (freed of the WS-Addressing crud for example) that makes it easy (almost as easy as the HTTP-based interface) to implement simple use cases (like a GET) by hand but is still SOAP-based, which lets it seamlessly enter library-driven territory when more advanced features are added (e.g. WS-Security, WS-Enumeration…). Rather than the current situation in which there is a protocol-level disconnect between the HTTP interface (easy to implement by hand) and the WS-Management interface (for which manually implementation is a cruel – and hopefully unusual – punishment).

So, Jean-Francois, where is this JMX-REST work going now?

While you’re on Jean-Francois’ blog, another must-read is his account of the use of Wiseman and Metro in the WS Connector for JMX Agent RI.

As a side note (that runs all the way to the end of this post), Jean-Francois’ blog is a perfect illustration of the kind of blogs I like to subscribe to. He doesn’t feel the need to post all the time. But when he does (only four entries so far this year, three of them “must read”), he provides a lot of insight on a topic he really understands. That’s the magic of RSS/Atom. There is zero cost to me in keeping his feed in my reader (it doesn’t even appear until he posts something). The opposite of what used to be conventional knowledge (that you need to post often to “keep your readers engaged” as the HP guidelines for bloggers used to say). Leaving the technology aside (there is nothing to RSS/Atom technologically other than the fact that they happen to be agreed upon formats), my biggest hope for these specifications is that they promote that more thoughtful (and occasional) style of web publishing. In my grumpy days (are there others?), a “I can’t believe United lost my luggage again” or “look at the nice flowers in my backyard” post is an almost-automatic cause for unsubscribing (the “no country for old IT guys” series gets a free pass though).

And Jean-Francois even manages to repress his Frenchness enough to not take snipes at people just for the fun of it. Another thing I need to learn from him. For example, look at this paragraph from the post that describes his use of Wiseman and Metro:

“The JAX-WS Endpoint we developed is a Provider<SOAPMessage>. Simply annotating with @WebService was not possible. WS-Addressing makes intensive use of SOAP headers to convey part of the protocol information. To access to such headers, we need full access to the SOAP Message. After some redesigning of the existing code we extracted a WSManAgent Class that is accessible from a JAX-WS Endpoint or a Servlet.”

In one paragraph he describes how to do something that IBM has been claiming for years can’t be done (implement WS-Management on top of JAX-WS). And he doesn’t even rub it in. Is he a saint? Good think I am here to do the dirty work for him.

BTW, did anyone notice the irony that this diatribe (which, by now, is taking as much space as the original topic of the post) is an example of the kind of text that I am glad Jean-Francois doesn’t post? You can take the man out of standards, but you can’t take the double standard out of the man.

[UPDATED 2008/6/3: Jean-Francois now has a second post to continue his exploration of marrying the Zen philosophy with the JMX technology.]


Filed under Application Mgmt, CMDB Federation, Everything, Implementation, IT Systems Mgmt, JMX, Manageability, Mgmt integration, Open source, SOAP, SOAP header, Specs, Standards, WS-Management

JSR262 public review ballot

The Public Review Ballot for JSR #262 that took place in the Executive Committee for SE/EE has closed. I am not familiar enough with the JCP process to know exactly what this milestone represents. But the results are interesting in any case.

The vote narrowly passed with 6 yes, 5 no and 1 abstain.

The overiding concern listed by the “no” voters (and several of the “yes” voters) is the fact that JSR262 uses WS-Management (a DMTF standard) which itself makes use of specifications that have been submitted to W3C but are not currently in the process of standardization (WS-Transfer, WS-Eventing, WS-Enumeration). And that it uses an older version of a now-standard specification (WS-Addressing).

SAP makes the most insightful comment: that this is not really a JCP problem but a DMTF problem. Hopefully the DMTF (and Microsoft, since it controls the fate of the specifications in question) will step up to the plate on this. This is likely to happen. Even if the DMTF and Microsoft didn’t care about making the JCP happy (but they do, don’t they?), they will run into similar issues if/when they push WS-Management towards ANSI/ISO standardization.

Next to this “non-standard dependencies” issue, there is only one technical issue mentioned. As you guessed, it’s IBM whining about the lack of a WSDL to feed their tools. This is becoming so repetitive that I may eventually stop making fun of it (but don’t hold your breath, I am not known for being very good at ending long-running jokes). It is pretty ironic to hear IBM claim that without that WSDL you can’t implement the spec on JAX-WS when you know that the wiseman reference implementation by Sun and HP is based on JAX-WS…

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Filed under Application Mgmt, Everything, IBM, Implementation, ISO, IT Systems Mgmt, JMX, Manageability, Microsoft, Specs, Standards, WS-Management, WS-Transfer

WS-ManagementHammer: don’t do it but if you are going to do it anyway then…

With the IBM/Microsoft/Intel/HP WSDM/WS-Management convergence now implicitly (if not yet officially) dead, it will be interesting to see what IBM is going to do with WSRF. WSRF is being used today, rarely explicitly but rather in an embedded fashion. People who use WSDM use it, people who use CDDLM use it, people who use the Globus Toolkit use it, etc. IBM could write off the convergence work (WS-ResourceTransfer, which was published as a draft, and WS-ResourceEnumeration and WS-EventNotification which were never published) and stick to using the existing WSRF specifications when they need the corresponding functionality. That’s what I hope they do.

Alternatively, they could decide to get the forceps out of the drawer. They can create a new, IBM-friendly (e.g. Fujitsu, CA, Cisco…) private consortium to take over the unfinished drafts (if the IBM/Microsoft/Intel/HP legal agreement allows this) or start new ones. Or they could go directly to W3C, OASIS or OGF and push for a new working group to do the work in the open (and since no-one else would really care about this work IBM should have relatively free hands there, the way Microsoft did in DMTF when IBM chose to boycott WS-Management). Why W3C would care and why OASIS or OGF would want to start commitees to obsolete their existing work is a separate question.

While I hope that IBM doesn’t try to push another pile of WS-* resouce management specifications on an industry that already has too many, if they do I hope that at least they’ll do it right. And that means doing away with the approach embedded in WS-ResourceTransfer. Having personally been involved in many iterations on this problem, I hope to have some insight to contribute.

Along the lines of the age-old parental advice “don’t do it but if you are going to do it then use a condom”, here is my advice to anyone thinking of doing another iteration on the WSRF question: don’t do it but if you are going to do it then be specific about what problem you are addressing.

First, let’s separate three scenarios.

Database query

WS-ResourceTransfer should not be seen as a way to query an XML database. Use XQuery for this.


While architecturally it should be possible to build RESTful applications on top of WS-Transfer‘s operations, this is simply not what is happening. WS-Transfer is being used either by CIM people (who get to it via WS-Management) or by big-SOA people (who get is as part of the whole WS-* stack) and neither of them is doing anything remotely RESTful. So just leave that aside and don’t see WS-ResourceTransfer as a way to do “fine-grained REST”. No REST user is loosing sleep over WS-ResourceTransfer being in limbo.

A flexible way to interact with a complex system

This is the use case that you should focus on. You have a system made up of many parts (e.g. a composite application or a server that is made of many components) that you can represent as an XML document. The XML repesentation contains some important information about the system, but it isn’t the system. There are identified resources within the system that have lifecycles, management capabilities and internal parameters. Not everything relevant is captured in the XML model. This is why it is different from an XML database.

In general, I don’t think that XML is the best way to represent complex IT systems. It has plenty of complications that are not relevant to IT management and it doesn’t elegantly support the representation of graphs, often the most natural way to represent such a system (more on this here). CMDBf, with its graph-oriented approach, is a better choice in general. But there are plenty of areas (especially smaller, well-defined, sub-systems) in which XML formats have been defined to represent systems. SCA and SML for example.

In the case where you are dealing with such an XML-described system, then there is value in standard ways to simplify interactions with the system and its parts. But here too, we need to distinguished different patterns rather than trying to handle them all in the same way.

Filtering/sequencing of returned data

Complex IT systems can generate a lot of configuration and/or monitoring data and often you only care for a small subset. For example, an asset record has dozens of elements (lease terms, owner, assigned user…) but you may only care to retrieve the date the lease expires. When you do a GET on the record, you want to qualify it by specifying that only that date needs to be returned. That’s what WS-RP, WS-RT and the WS-Management wsman:TransferFragment header allow. In a variation of this, you want all the data but you don’t want it in one go, you want to pull it piece by piece. That’s what WS-Enumeration gives you. The problem with all these specifications is that they only offer that feature when you are retrieving the resource representation (a WS-Transfer GET or equivalent), not for other operations. But how is this different from invoking an AirlineBooking operation and saying that you only want to be sent the confirmation code, not the full itinerary, equipment type, assigned seat, etc? Bundling this inside WS-RT (or equivalent) is not helpful. A generic SOAP header that can go on any message would be more appropriate (the definition of this header would need to pay special attention to security considerations, especially if the response is signed, because it could be abused to trick the server into sending, and signing, specifically-crafted messages).

Interacting with a sub-element of the system

If you have a handle to a computer system resource and you know that it has one CPU and that this CPU is represented by the /comp:CPU element of the system, why would you need to use some out-of-band discovery mechanism to interact with that CPU? It’s right there, you can see it, you can point to it. Surely there must be a way to address operations to it directly, right? WS-Management tries to do it with its wsman:Selector mechanism, but the selectors are not tied to the model and require, effectively, a separate out-of-band agreement for addressing. There shouldn’t be a need for such an additional agreement once an agreement has already been reached on the model.

What is needed is a way, for systems that have a known XML model, to address message to subpart by using the model itself to support that addressing. Call it SOAPy mashup if you want to feel like you are part of the cool kids. I described such a mechanism a while ago. In effect, it is an improvement on wsman:Selector that an eventual new iteration of WSRF should at least consider.

In some cases, namely when the operation is a WS-Transfer GET, this capability overlaps with the “filtering of returned data” capability. One way to look at it is that you are doing a GET at the level of the overall computer system and filtering the results down to the part that represents the CPU. Another way to look at it is that you are pinpointing the message to a subset of the model (the CPU part) and doing an unmodified GET on it. It doesn’t matter how you choose to think about it. In my proposal, these two ways produce the same message. Like the wave view and particle view of a photon, that in the end, describe the same physical entity with each being the best representation for a set of situations.

The problem with WS-RT and its predecessors is that it doesn’t recognise that this is just the intersection of two orthogonal concerns (filering of output versus addressing of sub-elements) and only handles that intersection.

Interacting with a set of resources as a set

The same kind of expression (typically XPath) that lets you point at a sub-element inside of a system also lets you point at a set of such sub-elements. But even though from an XPath perspective there isn’t much of a different (the first one just happens to return a nodeset that contains only one node), from an architectural perspective it is a very different use case. If you want to support such a use case then you have handle it as such and define all the associated semantics (sequential/parallel execution, fault handling, partial completion, resource-specific permissions…). You can’t just cross your fingers and assume that you get such features “for free” just because XPath can return a nodeset.

I know that this post illustrates a way of giving free advice that virtually ensures that it gets ignored. Similar (if you’ll allow the big stretch) to the way Chirac and Villepin were arguing againt an Iraq invasion in ways that probably reinforced the Bush administration’s determination to do it. When will the world finally learn to appreciate the oh-so-slightly obnoxious undertone that is inherently French (because, let me tell you, we’re not about to loose it)? At least, when my grandchildren ask me “where were you when IBM invented WS-ManagementHammer?” I can point to this post and say “I tried to stop it, I tried”.

[UPDATED 2008/5/15: How timely! Just after publishing this I find, via Coté, what looks like another example of French abrasiveness in the systems management world: the attitude, name and the way Jeff ends with a French-language quote make it quite likely that the “Jacques” person discounting the fact that his company’s SNMP agent is broken is indeed a compatriot. French obnoxiousness aside, and despite my respect for standards, my advice to Jeff is that if a given SNMP agent works with HP, IBM, BMC and CA you will probably save yourself time in the long run by finding a way to support it (even if it is not spec-compliant) rather than getting the vendor to change. There are lots of sites out there that work fine with Firefox and IE but are not compliant with Web standards. Good luck getting them all fixed.]

[UPDATED 2008/7/14: I don’t really plan to turn this post into a ongoing set of updates about “French attitude” but since today is Bastille Day I’ll point to this map of the world as seen from Paris. If I wasn’t on strike right now, I’d explain why the commenter is wrong to assert that “French self-deprecating humour” is rare.]


Filed under Everything, HP, IBM, IT Systems Mgmt, Mgmt integration, Microsoft, SCA, SML, SOAP, SOAP header, Specs, Standards, WS-Management, WS-ResourceTransfer, WS-Transfer, XMLFrag, XPath

The elusive XPath nodeset serialization

I have been involved in various capacity with five different specifications that define a GET (or GET-like) operation that takes as input an XPath expression used to pinpoint the subset of the XML document that should be retrieved (here is a quick history as of a couple of years ago, more has happened since). And I must shamefully admit that all but one are simply impossible to implement in an interoperable way.

That’s because they instruct implementers to return an XPath nodeset in the response SOAP message but say nothing about how to serialize the nodeset. While an XPath nodeset contains the kind of things that make up an XML document, it is not an XML document by itself. There is an infinite number of possible ways to serialized an XPath nodeset into XML. To have any hope of interoperability on this, a serialization algorithm has to be clearly described by the specification. Which hasn’t happened.

Let’s start with WS-ResourceProperties (WS-RP). It has a QueryResourceProperties operation that takes an XPath expression as input. The specification says that “the response MUST contain an XML serialization of the results of evaluating the QueryExpression against the resource properties document“. Great, thanks. The example provided happens to return a nodeset with only one node (a boolean), which is implicitly serialized into the text representation of that boolean. What if there is more than one node in the nodeset? What about other types of nodes?

Moving on to WS-Management, which defines a SOAP header that uses XPath to qualify a WS-Transfer GET request such that it only retrieves a subset of the target XML document. While it does a better job than WS-RP at describing the input (e.g. it specifies the context node and what namespace declarations are in scope for the XPath evaluation) it is even more cavalier than WS-RP in describing the output: “the output (lines 53-55) is like that supplied by a typical XPath processor and might or might not contain XML namespace information or attributes“. By “a typical XPath processor” we should understand MSXML I suppose. But as far as I know a “typical XML processor” doesn’t return XML, it returns language-specific data structures (e.g. a C# or Java object, like a nu.xom.Nodes instance). And here too, the examples only use single-node nodesets.

WS-ResourceTransfer (WS-RT) was supposed to be the convergence of these two efforts, so presumably it would have learned from their mistakes. While it is better written in general than its predecessors, it fails just as badly with regards to specifying the nodeset serialization. And once again, the example provided uses a nodeset with just one node.

And then came the CMDBf query operation which, for some unclear reason, was deemed in need of a built-in XPath transformation of records. As I pointed out in my review of CMDBf 1.0 at the time, this feature was added without taking the pain to define the XML serialization of the resulting nodeset. And there isn’t even an example of the XPath serialization.

It is sad in a way, but the only specification that acknowledges the problem and addresses it came before any of the four above even got started. It is the WSMF (Web Services Management Framework) work that we did at HP, and more specifically the “note on dynamic attributes and meta information” (not available at HP anymore but available from . This specification was the first one to define a GET operation that is qualified by an XPath expression. Unlike its successors it also explicitly narrowed down the types of nodes that could be selected (“The manager MUST NOT send as input an XPath statement that returns a nodeset containing nodes other than element, attribute and namespace nodes“). And for those valid types it described how to serialized them in XML (“When a node in the result nodeset is an attribute node, for the sake of the response it is serialized as an element node which has the same name as the name of the original attribute (see example 4 for an illustration). The element is in the same namespace as the namespace the attribute it represents is in. This applies to namespace nodes as well, they are serialized like an attributes in the xmlns namespace“). Turning an attribute into an element of the same QName might not be the smartest thing in retrospect (after all there may be an element by that QName already) but at least we recognized and addressed the problem.

But all is good now, I am told, because XPath 2.0 is here, along with a clean data model and a well-described serialization.

Not so. Anyone wanting to use XPath for a SOAP-based query language still would have to specify a serialization.

The first problem with the W3C serialization is that the XML output method doesn’t work for all nodesets. Try to use it on a nodeset that contains a top-level attribute node and you get error err:SENR0001. And even for the nodesets it accepts, it sometimes returns less-than-useful results. For example, if your XPath is of the form /employee/name/text() and you have four employees, the result will look something like this:

“Joe SmithKathy O’ConnorHelen MartinBrian Jones”

Concatenated text values without separators. I guess W3C is like a department store, they don’t offer complimentary wrapping anymore…

That’s why the nux.xom.xquery.ResultSequenceSerializer class had to define its own wrapping mechanims to produce a useful XML serialization. The API gives you the choice between the W3C_ALGORITHM and the WRAP_ALGORITHM.

Bottom line, and however much some would like to think of it that way, XPath (1 or 2) is not an XML subsetting/transformation mechanism. It could be used to create one (as XSLT does), but you have to do your own plumbing.

In addition to the technical aspects of this discussion, what else can be learned from this sad state of things? The fact that all these specifications define an XPath-driven query mechanism that is simply broken (beyond the simplest use cases) withouth anyone even noticing tells me that there isn’t a real need for full XPath query over SOAP (and I am talking about XPath 1.0, the introduction of XPath 2.0 in CMDBf is even more out there). A way to retrieve individual elements (and maybe text values) is all that is needed for 99% of the use cases addressed by these specifications. Users would be better served (especially in a version 1.0) by specifications that cover the simple case correctly than by overly generic, complex and poorly documented features. There is always time to add features later if the initial specification is successful enough that users encounter its limitations.


Filed under CMDB Federation, CMDBf, Everything, SOAP, Specs, Standards, Tech, W3C, WS-Management, WS-ResourceTransfer, XPath

System Center “Cross Platform Extension”: too many distractions

I was hoping that by the time MMS was over there would be more clarity about the “Cross Platform Extension” to System Center that Microsoft announced there. But most of the comments I have seen have focused on two non-technical aspects: Microsoft is interested in heterogeneous management and Microsoft makes use of open source. That’s also the focus of Coté’s coverage.

So what? Is it still that exciting, in 2008, to learn that Microsoft recognizes that Linux and OSS are major players in enterprise computing? If Steve Ballmer eventually gets hold of Yahoo, do you think his first priority will be to move all the servers to Windows or to build up its search and advertising audience? It’s been now 10 years since the Halloween documents came out. They can be seen as the start of Microsoft’s realization that Linux/OSS are here for good. It is not surprising to see that one of their main authors is now the driving force behind WS-Management, an effort that illustrates the acceptance of heterogeneity and the need to deal with it (on Microsoft’s terms if possible, of course). The WS-Management effort started years ago and it was a clear sign that Microsoft knew it had to tackle heterogeneous management (despite the reassuring talk that “it’s all about making Windows the most manageable platform” to HP and others). Basically, Microsoft is using WS-Management to support heterogeneity without having to do too much work: by creating an industry standard that everyone writes to and that Microsoft uses internally. Heterogeneous management is intrinsic to DSI if DSI is to be anything more than a demo.

But all of this was known before MMS 2008 to anyone who was paying attention. Instead of all this Microsoft/OSS/heterogeneous talk, I am a lot more interested in the technical aspects of the “Cross Platform Extension”.

OpenPegasus has been around for a long time, as a C++ CIMOM with a bunch of associated providers and CIM-XML interoperability over HTTP with CIM clients. I don’t know where WS-Management support was on the OpenPegasus development timeline, but even without Microsoft getting involved it would have eventually happened. And this should have been sufficient for System Center to access the CIMOM (BTW, does System Center not support CIM-XML when WS-Management is not present and if it does then what is different in practice with WS-Management?).

I can see how Microsoft would bring some extra (and much welcome) development resources for the WS-Management implementation (BTW the guys at Intel already have an open-source C implementation of WS-Management) as well as some extra marketing/visibility/distribution. Nice, but not earth-shattering. Do they bring anything else to OpenPegasus?

And what else is in the “Cross Platform Extension” in addition to an OpenPegasus WS-Management-capable CIMOM? Is there any extra modeling capability beyond CIM? Any Microsoft-specific classes? Any discovery/reconciliation capability? How much actual configuration management versus just monitoring? Security? Health models? Desired state management? Or is it just a WS-Management CIMOM? Any pointer to specific information is welcome.

Of course the underlying question is whether others than Microsoft can manage resources that have an OpenPegasus-based System Center management pack on them. The Open Management Consortium guys have talked about an open management agent. Could, against all expectations, Microsoft be the one delivering it?

In the IT management world, there are the big 4 (HP, BMC, CA and IBM), the little 4 (Zenoss, Hyperic, GroundWorks and openQRM) and the mighty 3 (Oracle, Microsoft and EMC). Sorry John, I am reclaiming the use of the “mighty” term: your “mighty 2” (or 2.5) are really still the “little 2” (or 2.5). At least for now.

The interesting thing is that in that industry configuration there are topics on which the little ones and the mighty ones share common interests. For example, the big 4 have a lot more management packs for all kinds of resources, built up over the years. Some standard-based mechanism that partially resets the stage helps the little ones and the mighty ones better compete against the big 4. Even better if it has an attractive (and extensible) implementation ready in the form of an agent. But let’s be clear that it takes more than a CIMOM to make a management pack. You need domains-specific expertise in the form of health models, deployment/configuration scripts and/or descriptors, configuration validation, role management etc. Thus my questions about what else (beyond CIM over WS-Management) Microsoft is bringing to the table. SML and CML are supposed to address this space, but I didn’t hear them mentioned once in the MMS coverage.

[UPDATED on 2008/5/7: Another perspective on Microsoft and open source: Microsoft Ex-Pats Developing Open Source Software Outside of Redmond]

[UPDATED 2008/5/7: I got an answer to the question about System Center support for CIM-XML: it doesn’t have it. So indeed it’s either WS-Management of WMI. If you’re a Linux box, that means it’s WS-Management.]

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Filed under CA, Everything, HP, IBM, IT Systems Mgmt, Manageability, Mgmt integration, Microsoft, Open source, Oracle, SML, Standards, WS-Management, Yahoo

WS-Transfer, its WSDL and its WS-I compliance: the art of engineered uselessness

Several years ago, Chris Ferris wrote a blog entry in which he explains that WS-Transfer is not WS-I Basic Profile (BP) compliant.

Chris’ main point is correct: the WSDL document in appendix II of the WS-Transfer specification is not compliant with the WS-I Basic Profile. But what does this mean and why should one care?

If you search for the word “wsdl” in WS-Transfer, you first find it in the table that declares namespace prefixes used in the specification. But the prefix is not used in the specification, so it could just as well be removed from that table.

We see it next mentioned in the “compliance” boilerplate where it is declared to be the least authoritative of all information in the specification.

The next occurrence is all the way down in section 8, as a reference to the WSDL 1.1 W3C note. The only place where that reference is used, is further below, in Appendix II.

In short, for all practical purposes there is no mention of WSDL in WS-Transfer except for this one appendix that contains a WSDL document. Since there is no MUST or REQUIRED statement that refers to it, it is at best a testing tool that one can use to validate WS-Transfer messages produced. There is no requirement at all that the implementation produces that WSDL (e.g. as a response to a WS-MeX request) or consumes it.

And if you look at the content of the WSDL, it is mostly XML gymnastics aimed at creating “empty” and “any” types to express almost nothing useful about the messages sent and received.

You don’t have to take my statement that the WS-Transfer WSDL is useless at face value. Here are two other proofs:

  • Chris doesn’t just point out the WS-I BP violation in the WS-Transfer WSDL, he also proposes a way to fix it. He writes: “I actually think that a more appropriate approach to handling WS-Transfer’s ‘Get’ would be to specify the output message as you would any doc-literal operation and merely annotate the operation with the appropriate wsa:Action attribute values” (he also provides an example). And he is perfectly right. If you really want a WSDL for your WS-Transfer operations, create one that is specific to the resource type (server, toaster…) that you are dealing with. By definition that WSDL can’t be baked into the model-agnostic WS-Transfer specification. While Chris doesn’t say it, the natural conclusion of his remark is that there is not point for a WSDL in WS-Transfer (because any resource-agnostic WSDL is useless).
  • The WS-Transfer XSD and WSDL have been modified, sometimes in backward-incompatible ways, without changing the target namespace. From the original version to the first W3C submission, some minor changes (message names, introduction of WS-Addressing). From the first W3C submission to the current submission, some potentially backward-incompatible changes (the GET input can now be non-empty, the CREATE response can now contain anything as a result of trying to support different versions of WS-Addressing). On top of that, all these XSD and WSDL documents embedded in various versions of the spec are “non-normative”. The normative versions are said to be the ones at (XSD, WSDL). Those have not changed, which means that both versions on the W3C web site contain an incorrect version of the XSD/WSDL in the spec. Shouldn’t that lack of XML hygiene be a big deal for a specification that is implemented (via WS-Management, which references the W3C submission) in resources with long product development cycles, such as servers from Dell, HP and others that have WS-Management support directly on the motherboard? It would, if the XSD and WSDL had any relevance for the implementers. The fact that there was no outcry is yet another proof that the WS-Transfer XSD and the WSDL are irrelevant.

So yes, Chris is right that the WS-Transfer WSDL (BTW all versions have the problem that Chris describes even though it could have been fixed in a backward-compatible way when the WSDL was altered) is not WS-I BP compliant. But since that WSDL is useless anyway, this shouldn’t keep anyone up at night. The WS-Transfer WSDL serves no purpose other than to annoy people who like things to be WS-I BP compliant.

But is it just the WS-Transfer WSDL that’s useless, or it is all of WS-Transfer?

I am not planning to go into WS-* vs. REST territory here. To those who are confused by the similarity between the names of WS-Transfer operations and HTTP methods and see WS-Transfer as a way to do “REST over SOAP” I’ll just point out that WS-Transfer is rarely used on its own but rather in conjunction with many other SOAP messages (like those defined by WS-Eventing and WS-Enumeration, plus countless custom operations). So much for uniform interfaces. WS-Transfer, at least as it is used today, is not about REST.

Rather, the reasons why I question the usefulness of WS-Transfer are more pragmatic than architectural. I can think of three potential justifications to carve out WS-Transfer as a separate specification, none of which is really convincing at this point in time.

The first reason is simply to avoid repeating the same text over and over again. If many specifications are going to describe the same SOAP message, just describe it once and refer to that description. Sounds good. But I know of three specifications that use WS-Transfer: WS-Management, WS-MeX and the Devices Profile for Web Services.

WS-MeX and the Devices Profile only use the GET operation. Which means that the only specification text that they can re-use from WS-Transfer is something like “send an empty get request and get something back”. WS-Transfer can’t say what that something is, only the domain-specific specifications can. As a result, you are spending as much time referencing WS-Transfer as would be spent defining a simple GET operation. For all practical purposes, you can implement WS-MeX and the Devices Profile without ever reading WS-Transfer.

The second potential reason is to provide a stand-alone piece of functionality that can be implemented once (e.g. as a library/module) and re-used for different purposes. Something that automatically kicks in when a WS-Transfer wsa:Action is detected. Think of a stand-alone encryption/decryption library for example, that looks for specific SOAP headers. Or WS-Eventing, for which a library can take over the task of managing the subscription lifecycle. Except WS-Transfer defines so little that it’s not clear what a stand-alone WS-Transfer implementation would do. Receive messages and do what with them? It is so tied to the back-end that there isn’t much you can do in a general fashion. Unless you are creating a library for a database product and you see WS-Transfer as a query interface for your database. But this only makes sense if you want to provide more fine-grained access to the XML content, which WS-Transfer does not do.

Which takes us to the third potential value of WS-Transfer, as a foundational specification on which to build extensions. Of the three this is the only one that I believed in at some point. WS-ResourceTransfer (WS-RT) was the main attempt at doing this. Any service that uses WS-Transfer could, via the magic of the SOAP processing model, offer a more precise/powerful access to the resources. But while this was possible in theory it hasn’t really panned out in practice for many reasons:

  • Some people (hints: Armonk; Blue) pushed hard to put WS-RT instructions in the body rather than in headers, seriously compromising its ability to seamlessly compose with existing SOAP messages.
  • WS-MeX and the Devices Profile typically deal with documents small enough that manipulating them as a whole is rarely a problem. This only leaves WS-Management which has its own “fragment transfer” mechanism so it doesn’t really need a stand-alone mechanism.
  • XQuery is now developing support for an update capability.

What then is left, in the Spring of 2008, to justify the need for WS-Transfer as a separate layer, rather than considering it an integral part of WS-Management? Not much. WS-MeX, in an earlier version, used to define its own GET operation and it wouldn’t be any worse off if it had stayed that way (or returned to it). Ditto for the Device Profile. At this point, it’s mostly a matter of pragmatically cleaning up the mess without creating another one.

In retrospect (color me partially guilty), maybe one shouldn’t use the same architectural rules when attempting to design an interoperable standard stack for an industry than when refactoring a software project. Maybe one should resist the urge to refactor the “code” (or rather the PowerPoint stack) every time one detects the smallest conceptual redundancy. There is a cost in constant changes. There is a cost in specification cross-dependencies. WSDM experienced it firth hand with the different versions of WS-Addressing (another dependency that didn’t need to be). WS-Management is seeing it from the perspective of standardization.

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Filed under Everything, Microsoft, SOAP, Specs, Standards, WS-Management, WS-ResourceTransfer, WS-Transfer, XQuery

JSR262 (JMX over WS-Management) public review

If you care about exposing or accessing MBeans via WS-Management, now is a good time to read the public review draft of the JSR262 spec.

JSR262 is very much on the “manageability” side of the “manageability vs. management integration” chasm, which is not the most exciting side to me. But more commonality in manageability protocols is good, I guess, and this falls inside the WS-Management window of opportunity so it may help tip the balance.

There is also a nice white paper which does a nice job of retracing the history from JMX to JMX Remote API to JSR 262 and the different efforts along the way to provide access to the JMX API from outside of the local JVM. The white paper is actually too accurate for its own good: it explains well that models and protocols should be orthogonal (there is a section titled “The Holy Grail of Management: Model, Data and Protocol Independence”) which only highlights the shortcomings of JSR262 in that regard.

In a what looks from the outside like a wonderful exercise of “when you have a hammer” (and also “when you work in a hammer factory” like the JCP), this whole Java app management effort has been API-driven rather than model-driven. What we don’t get out of all this is a clearly defined metamodel and a set of model elements for Java apps with an XML serialization that can be queried and updated. What we do get is a mapping of “WS-Management protocol operations to MBean and MBean server operations” that “exposes JMX technology MBeans as WS-Management resources”.

Yes it now goes over HTTP so it can more easily fool firewalls, but I am yet to see such a need in manageability scenarios (other than from hackers who I am sure are very encouraged by the development). Yes it is easier for a non-Java endpoint to interact with a JSR262 endpoint than before but this is an incremental improvement above the previous JMX over RMI over IIOP because the messages involved still reflect the underlying API.

Maybe that’s all ok. There may very well not be much management integration possible at the level of details provided by JMX APIs. Management integration is probably better served at the SCA and OSGi levels anyway. Having JSR262 just provide incremental progress towards easier Java manageability by HP OVO and the like may be all we should ask of it. I told some of the JSR262 guys, back when they were creating their own XML over HTTP protocol to skirt the WS-Management vs. WSDM debate, that they should build on WS-Management and I am glad they took that route (no idea how much influence my opinion had on this). I just can’t get really excited about the whole thing.

All the details on the current status of JSR262 on Jean-Francois Denise’s blog.


Filed under Everything, JMX, Manageability, Mgmt integration, Specs, Standards, WS-Management

DMTF members as primary voters?

I just noticed this result from the 2007 DMTF member survey (taken a year ago, but as far as I can tell just released now). When asked what their “most important interoperability priority” is, members made it pretty clear that they want the current CIM/WBEM infrastructure fixed and polished. They seem a lot less interested in these fancy new SOAP-based protocols and even less in using any other model than CIM.

It will be interesting to see what this means for new DMTF activities, such as CMDBf or WS-RC, that are supposed to be model-neutral. A few possibilities:

  • the priorities of the members change over time to make room for these considerations
  • turn-over (or increase) in membership brings in members with a different perspective
  • the model-neutral activities slowly get more and more CIM-influenced
  • rejection by the DMTF auto-immune system

My guess is that the DMTF leadership is hoping for #1 and/or #2 while the current “base” (to borrow from the US election-season language) wouldn’t mind #3 or #4. I am expecting some mix of #2 and #3.

Pushing the analogy with current US political events further than is reasonable, one can see a correspondence with the Republican primary:

  • CIM/WBEM is Huckabe, favored by the base
  • CMDBf/WS-RC/WS-Management etc is Romney, the choice of the party leadership
  • At the end, some RDF and HTTP-based integration-friendly approach comes from behind and takes the prize (McCain)

Then you still have to win the general election (i.e. industry adoption of whatever the DMTF cooks up).

[UPDATED 2008/2/7: the day after I write this entry, Romney quits the race. Bad omen for CMDBf and WS-RC? ;-) ]

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Filed under CMDB Federation, CMDBf, DMTF, Everything, Standards, WS-Management

How not to re-use XML technologies

I like XML. Call me crazy but I find it relatively easy to work with. Whether it is hand-editing an XML document in a text editor, manipulating it programmatically (as long as you pick a reasonable API, e.g. XOM in Java), transforming it (e.g. XSLT) or querying an XML back-end through XPath/XQuery. Sure it carries useless features that betray its roots in the publishing world (processing instructions anyone?), sure the whole attribute/element overlap doesn’t have much value for systems modeling, but overall it hits a good compromise between human readability and machine processing and it has a pretty solid extensibility story with namespaces.

In addition, the XML toolbox of specifications is very large and offers standard-based answers to many XML-related tasks. That’s good, but when composing a solution it also means that one needs to keep two things in mind:

  • not all these XML specifications are technically sound (even if they carry a W3C stamp of approval), and
  • just because XML’s inherent flexibility lets one stretch a round hole, it doesn’t mean it’s a good idea to jam a square peg into it.

The domain of IT management provides examples for both of these risks. These examples constitute some of the technical deficiencies of management-related XML specifications that I mentioned in the previous post. More specifically, let’s look at three instances of XML mis-use that relate to management-related specifications. We will see:

  • a terrible XML specification that infects any solution it touches (WS-Addressing, used in WS-Management),
  • a mediocre XML specification that has plenty of warts but can be useful for a class of problems, except in this case it isn’t (XSD, used in SML), and
  • a very good XML specification except it is used in the wrong place (XPath, used in CMDBf).

Let’s go through them one by one.

WS-Addressing in WS-Management

The main defect of WS-Management (and of WSDM before it) is probably its use of WS-Addressing. SOAP needs WS-Addressing like a migraine patient needs a bullet in the head (actually, four bullets in the head since we got to deal with four successive versions). SOAP didn’t need a new addressing model, it already had URIs. It just needed a message correlation mechanism. But what we got is many useless headers (like wsa:Action) and the awful EPR construct which solves a problem that didn’t exist and creates many very real new ones. One can imagine nifty hacks that would be enabled by a templating mechanism for SOAP (I indulged myself and sketched one to facilicate mash-up style integrations with SOAP) but if that’s what we’re after then there is no reason to limit it to headers.


The words “Microsoft” and “bully” often appear in the same sentence, but invariably “Microsoft” is the subject not the object of the bullying. Well, to some extent we have a reverse example here, as unlikely as it may seem. Microsoft created an XML-based meta-model called SDM that included capabilities that looked like parts of XSD. When they opened it up to the industry and floated the idea of standardizing it, they heard back pretty loudly that it would have to re-use XSD rather than “re-invent” it. So they did and that ended up as SML. Except it was the wrong choice and in retrospect I think it would have been better to improve on the original SDM to create a management-specific meta-model than swallow XSD (SML does profile out a few of the more obscure features of XSD, like xs:redefine, but that’s marginal). Syntactic validation of documents is very different from validation of IT models. Of course this may all be irrelevant anyway if SML doesn’t get adopted, which at this point still looks like the most likely outcome (due to things like the failure of CML to produce any model element so far, the ever-changing technical strategy for DSI and of course the XSD-induced complexity of SML).

XPath in CMDBf

I have already covered this in my review of CMDBf 1.0. The main problem is that while XML is a fine interchange format for the CMDBf specification, one should not assume that it is the native format of the data stores that get connected. Using XPath as a selector language makes life difficult for those who don’t use XML as their backend format. Especially when it is not just XPath 1.0 but also the much more complex XPath 2.0. To make matters worse, there is no interoperable serialization format for XPath 1.0 nodesets, which will prevent any kind of interoperability on this. That omission can be easily fixed (and I am sure it will be fixed in DMTF) but that won’t address the primary concern. In the context of CMDBf, XPath/XQuery is an excellent implementation choice for some situations, but not something that should be pushed at the level of the protocol. For example, because XPath is based on the XML model, it has clear notions of order of elements. But what if I have an OO or an RDF-based backend? What am I to make of a selector that says that the “foo” element has to come after the “bar” element? There is no notion of order in Java attributes and/or RDF properties.


My name (in the context of my previous job at HP) appears in all three management specifications listed above (in increasing level of involvement as contributor for WS-Management, co-author for SML and co-editor for CMDBf) so I am not a neutral observer on these questions. My goal here is not to de-associate myself from these specifications or pick and choose the sections I want to be associated with (we can have this discussion over drinks if anyone is interested). Some of these concerns I had at the time the specifications were being written and I was overruled by the majority. Other weren’t as clear to me then as they are now (my view of WS-Addressing has moved over time from “mostly harmless” to “toxic”). I am sure all other authors have a list of things they wished had come out differently. And while this article lists deficiencies of these specifications, I am not throwing the baby with the bathwater. I wrote recently about WS-Management’s potential for providing consistency for resource manageability. I have good hopes for CMDBf, now in the DTMF, not necessarily as a federation technology but as a useful basis for increased interoperability between configuration repositories. SML has the most dubious fate at this time because, unlike the other two, it hasn’t (yet?) transcended its original supporter to become something that many companies clearly see fitting in their plans.

[UPDATED 2008/3/27: For an extreme example of purposely abusing XML technologies (namely XPath in that case) in a scenario in which it is not the right tool for the job (graph queries), check out this XPath brain teasers article.]


Filed under CMDB Federation, CMDBf, Everything, IT Systems Mgmt, Microsoft, SML, SOAP, SOAP header, Specs, Standards, Tech, WS-Management, XOM

Manageability, management integration and WS-Management

It is pretty clear by now that, whether or not it becomes ubiquitous, WS-Management will be around for quite some time as a protocol for resource manageability. Its inclusion in a large number of manageable products with long development cycles (servers, devices, operating systems…) ensures this. But I wonder whether it will also be useful for management integration.

The difference between manageability and management integration may not seem obvious, but it is important. To simplify, a manageability protocol is something that allows you to remotely manage a resource without having to deploy an agent on it. It lets you read the CPU load on a server. It lets you retrieve a list of instances running in a process engine. It lets you reboot a machine. It lets you access the logs of an application. It lets you receive alerts about a resource. Management integration, on the other hand, lets you create management solutions. For example, it’s what you do when you create a management dashboard that presents information aggregated from several management data repositories (e.g. a CMDB, a metrics store and a SOA registry). Or when you run system-wide validation rules to govern a complex system. Or when you perform automated root cause analysis.

Here is another way to illustrate the difference: CIM is useful for manageability. The more recent standardization efforts in the management world (SML, CMDBf) have been focusing on management integration. To some extent, you can even use that difference as the shortest answer to the common question “what is the relationship/difference between SML and CIM”: CIM is designed for manageability and SML for management integration.

The difference between manageability and management integration isn’t alway clear-cut. There are scenarios that could be argued to fall in either category. And management integration scenarios often involve manageability interactions. But if you try to implement management integration scenarios by working at the manageability level, you very quickly get bogged-down. And even if you fight your way to completion, the resulting integration is too brittle to be of any long-term use. You need a level of abstraction over manageability. This is very similar to integration problems in other domains, and this is where SOA comes in, as a design approach to provide resilience and flexibility for management integration. SOA doesn’t help much in manageability scenarios. It can be useful for management integration.

People working on using Web services for management never had a shared understanding of this distinction. If you look at Microsoft’s early scenarios for WS-Management (and their partner list), it is clear that they were focused on manageability, mostly of the Windows OS, the computers it runs on and the devices connected to these computers. On the other hand, when my colleagues at HP Software and I produced WSMF and later worked on WSDM and WS-Management, it was management integration that we cared most about. We didn’t really care much to put a SOAP wrapper around manageability operations. But we understood that this was also happening and it made sense to share tools and expertise between the two sets of scenarios, especially since, as mentioned above, they overlap.

What happened is that manageability is the only place where WS-Management took hold. One reason is that Microsoft was the main force pushing this adoption and this is where they were pushing it. Another is that, with CIM/HTTP and SNMP, the use of standard protocols for manageability was understood (and the prospect of better tools and better alignment with mainstream distributed software technologies was mostly welcomed by that community).

But in my mind, the use of SOAP made by WS-Management is mostly suited for management integration scenarios. In the manageability case, it’s mostly overhead. You don’t really need security beyond what SSL offers. You don’t really need routing through intermediaries. You don’t really need reliable messaging or the flavor of “transactionality” that the WS-* specifications provide. You don’t really need asynchronous messaging. You don’t really need fine-grained get/set operations (when dealing with one resource, operations at the level of the entire representation are often sufficient). Which is why I can’t help shaking my head when I see WS-Management used for manageability and not for management integration. Kind of like using an SUV that can carry eight people over mountains to carry one person to the hairdresser. Crazy, I know.

Leaving the SUV analogy aside, it’s not that WS-Management is perfectly designed for management integration either, not by a long shot. Which takes us to a third reason (and there are more) why WS-Management is not being used in management integration scenarios: it has technical deficiencies as do many of the other specifications recently created for management integration. That’s the topic of the next post.

[UPDATED 2009/6/26: EMC’s Chuck Hollis explains “management versus manageability” (he calls management “service orchestration” and manageability “element management”) in a much simpler way than I was able to. And he hints at upcoming management orchestration software from EMC (time will tell whether they missed out on BladeLogic and Opsware or made the right choice to let others acquire them). It will be interesting to see which of the 7 roads to IT automation middleware they take.]


Filed under Everything, IT Systems Mgmt, Manageability, Mgmt integration, SOAP, WS-Management

The window of opportunity for WS-Management

There is a narrow window of opportunity for WS-Management to become a unifying force that helps lower the need for management agents. Right now, WS-Management is still only “yet another manageability protocol”. Its adoption is growing but there isn’t much you can do with it that you can’t do through some other way (what resources today are only manageable through WS-Management?) and it is not so widely supported that you can get away with supporting just WS-Management.

I see two main reasons keeping pragmatic creators of IT resources (hardware and software) from more widely using WS-Management to expose the manageability capabilities of their resources. The first one, that I will cover here, is the fear of wasting development resources (and the lack of customer demand). The second one, that I will cover in a later post, is the complexity introduced by some technical choices in WS-Management.

There is plenty of uncertainty around the status and future of WS-Management. This means that any investment in implementing the specification is at risk of having to be later thrown away. It also means that customers, while they often mention it as part of a check-list, understand that at this point WS-Management doesn’t necessarily give them the investment protection that widely-supported stable standards provide. And as such they are receptive when vendors explain that at this point there really isn’t a stable standard for manageability that goes across domains and the best they can get is support for a patchwork of established specifications like SNMP, JMX, CIM/HTTP, WMI, etc.

One source of this uncertainty about WS-Management comes from the fact that there is an equivalent standard, WSDM, that came out of OASIS. But at this point, it is pretty clear that WSDM is going nowhere. Good metrics are hard to come by, but if you compare the dates of last commit activity in the three open-source WS-Management implementations that I know of (Openwsman, Wiseman and the WS-Management module of SOA4D) to that of the Muse implementation of WSDM, you are comparing ages in hours/days to ages in months. Another way is to look at the sessions in the Web services track at the recent Management Developers Conference: six presentations around WS-Management (including an intriguing Ruby on Rails module) compared to one for WSDM. Unless your company is an IBM-only account, WSDM isn’t a useful alternative to WS-Management (and it’s not due to technical inferiority, I still prefer WSDM MUWS to WS-Management on that point but it’s largely irrelevant).

The more serious concern is that, back when it wasn’t clear that the industry would pick WS-Management over WSDM, an effort was launched to reconcile the two specifications. That effort, often refered to as the WS-Management/WSDM convergence, is private so no-one outside of the four companies involved know what is happening. The only specification that has come out at this point is a draft of WS-ResourceTransfer in summer 2006 (I don’t include WS-ResourceCatalog because even though it came out of the same group it provides features that are neither in WS-Management nor in WSDM so it is not really part of converging them). What is happening now? The convergence effort may have died silently. Or it may be on the brink of releasing a complete new set of specifications. Or it may have focused on a more modest set of enhancements to WS-Management. Even though I was in the inside until a few months ago, I am not feigning ignorance here. There is enough up in the air that I can visualize any of these options realized.

This is not encouraging to people looking to invest their meager development resources to improve manageability interfaces on their products. What if they put work in WS-Management and soon after that Microsoft, IBM, HP and Intel come out with a new set of specifications and try to convince the industry to move from WS-Management to that new set of specifications? Much safer to stay on the sidelines for now. The convergence is a source of FUD preventing adoption of WS-Management. It is, on the other hand, a lifeline for WSDM because it provides a reason for those who went with WSDM to wait and see what happens with the convergence before moving away from WSDM.

Even before leaving HP, I had come to the conclusion that it was too late for the convergence to succeed. This doesn’t imply anything about HP’s current position on the topic, which I am of course not qualified to represent. But I just noticed that the new HP BTO chief architect doesn’t seem too fond of WS-*.

Even if the convergence effort manages to deliver the specifications it promised (including an update of WS-ResourceTransfer which is currently flawed, especially its “partial put” functionality), it will be years before they get published, interop-tested, submitted and standardized. Will there be appetite for a new set of WS-* specifications at that point? Very doubtful. SOAP will be around for a long time, but the effort in the SOAP community is around using the existing set of specifications to address already-identified enterprise integration problems. The final stage in the production of any good book, article or even blog post (not that this blog is a shining example) is to pair-down the content, to remove anything that is not essential. This is the stage that the SOAP world is in, sorting through the deluge of specifications to extract and polish the productive core. New multi-spec frameworks need not apply.

If there is to emerge a new, comprehensive, framework for web-based manageability, it won’t be the WS-Management/WSDM convergence. It probably won’t use SOAP (or at least not in its WS-Addressing-infected form). It may well use RDF. But it is not in sight at this point. So for now the choice is whether to seize the opportunity to create a widely-adopted standard on the basis of WS-Management (with all its flaws) or to let the window of opportunity close, to treat WS-Management as just another manageability tool in the toolbox and go on with life. Until the stars line up in a few years and the industry can maybe take another stab at the effort. To a large extent, this is in the hands of Microsoft, IBM, HP and Intel. Ironically, the best way for those who want nothing to do with SOAP to prevent SOAP from being used too much for manageability (beyond where WS-Management is already used) is to keep pushing the convergence (which is very much SOAP based) in order to keep WS-Management contained.


Filed under DMTF, Everything, IT Systems Mgmt, Standards, WS-Management, WS-ResourceTransfer