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Archive for the 'CMDB Federation' Category

06
Nov
2007

Illustrative algorithm for CMDBf 1.0 Query operation

by William Vambenepe

When I posted an algorithm for the server side implementation of a CMDBf Query call for version 0.95 of the specification, the interoperability testing session based on that version was over and I was pretty sure no-one but those of us who participated in that session would write an implementation of 0.95. But I published the algorithm anyway since I thought it was helpful to anyone who wanted to understand the specification in depth, even if they were not implementing it. Now that 1.o is out, there is a much higher probability of people implementing the specification, so I figured it would be worth updating the algorithm to take into account the changes from 0.95 to 1.0. So here it is.

One caveat. This algorithm assumes that the query request does not make use of the xpathExpression element because, as I have explained in my review of CMDBf 1.0, I don’t think interoperability is achievable on this feature in the current state of the specification.

As a note of caution, the previous version of the algorithm was backed by my implementation of CMDBf 0.95 for the interoperability testing, so I felt pretty confident about it. For this version of the algorithm I have not written a corresponding implementation and I have not done interoperability testing with anyone, it’s just based on my reading of the specification. The handling of depthLimit in particular is a little tricky and needs to be validated by implementation (what with creating a bunch of dummy item and relationship templates with temporary names and later going back to the original template names), please let me know if you find it flawed.

And, as previously, this is in no way an optimal implementation strategy. It is the most direct and obvious set of steps that I can come up with to implement the Query call in a way that exactly conforms to the specification. There are lots of ways to make this go faster, such as the ones I mentioned in a previous post (e.g. breaking out of loops once an instance has been removed, or not recalculating L1 and L2 over and over again for relationships in the same working set that share a source/target) plus new ones such as being smarter than my brute-force approach to handling depthLimit (in step 2).

All this said, here is the algorithm:

1) for each itemTemplate, calculate the set of all items (including relationships since they are a subclass of item) that obey the instanceIdConstraint and recordConstraint elements in the template (if present). Call this the working set for the itemTemplate.
2) for each relationshipTemplate RT that has a depthLimit element:

2.1) for i ranging from 1 to the value of maxIntermediateItems for RT:

2.1.1) create an itemTemplate that is an exact copy of the itemTemplate referenced by RT’s sourceTemplate, except that it has a new, unique temporary id (keep a record linking that new id to the id of the original source itemTemplate).
2.1.2) create an itemTemplate that is an exact copy of the itemTemplate referenced by RT’s targetTemplate, except that it has a new, unique, temporary id (keep a record linking that new id to the id of the original target itemTemplate).
2.1.3) for j ranging 1 from i:

2.1.3.1) create an itemTemplate that is an exact copy of the itemTemplate referenced by RT’s intermediateItemTemplate, except that it has a new, unique, temporary id (keep a record linking that new id to the id of the original intermediary itemTemplate).
2.1.3.2) create a relationshipTemplate that is an exact copy of RT, except that its source is the itemTemplate created in the previous iteration of the current loop (or the itemTemplate created in step 2.1.1 if j=1), its target is the itemTemplate created in the previous step and it has a new, unique, temporary id (keep a record linking that new id to RT’s id).

2.1.4) create a relationshipTemplate that is an exact copy of RT, except that its source is the last itemTemplate created in the 2.1.3 loop, its target is the itemTemplate created in 2.1.2 and it has a new, unique, temporary id (keep a record linking that new id to RT’s id).

3) for each relationshipTemplate calculate the set of all relationships that obey the instanceIdConstraint and recordConstraint elements in the template (if present). Call this the working set for the relationshipTemplate.
4) set need_to_loop = true
5) while (need_to_loop == true)

5.1) set need_to_loop = false
5.2) for each relationshipTemplate RT

5.2.1) let ITsource be the itemTemplate that is referenced as sourceTemplate by RT. Calculate the set of all items (including relationships since they are a subclass of item) that obey at least one of the instanceIdConstraint elements in ITsource (assuming there is at least one such element) and all the recordConstraint elements in ITsource. Call this the working set for ITsource.
5.2.2) let ITtarget be the itemTemplate that is referenced as targetTemplate by RT. Calculate the set of all items (including relationships since they are a subclass of item) that obey at least one of the instanceIdConstraint elements in ITtarget (assuming there is at least one such element) and all the recordConstraint elements in ITtarget. Call this the working set for ITtarget.
5.2.3) for each relationship R in the working set for RT

5.2.3.1) if the source of R is not in the working set for ITsource, then remove R from the RT working set
5.2.3.2) if the target of R is not in the working set for ITtarget, then remove R from the RT working set
5.2.3.3) if RT has a source/@minimum or a source/@maximum attribute

5.2.3.3.1) find the list L1 of all relationships in the working set for RT that have the same source as R
5.2.3.3.2) if RT has source/@minimum and the cardinality of L1 is less than this minimum then remove all relationships in L1 from the RT working set
5.2.3.3.3) if RT has source/@maximum and the cardinality of L1 is more than this maximum then remove all relationships in L1 from the RT working set

5.2.3.4) if RT has a target/@minimum or a target/@maximum attribute

5.2.3.4.1) find the list L2 of all relationships in the working set for RT that have the same target as R
5.2.3.4.2) if RT has target/@minimum and the cardinality of L2 is less than this minimum then remove all relationships in L2 from the RT working set
5.2.3.4.3) if RT has target/@maximum and the cardinality of L2 is more than this maximum then remove all relationships in L2 from the RT working set

5.3) for each itemTemplate IT:

5.3.1) let sourceRTset be the set of all relationshipTemplates that references IT as its sourceTemplate
5.3.2) let targetRTset be the set of all relationshipTemplates that references IT as its targetTemplate
5.3.3) for each item I in the IT working set

5.3.3.1) for each relationshipTemplate sourceRT in sourceRTset, if there is no relationship in the working set for sourceRT that uses I as its source, remove I from the IT working set and set need_to_loop to true
5.3.3.2) for each relationshipTemplate targetRT in targetRTset, if there is no relationship in the working set for targetRT that uses I as its source, remove I from the IT working set and set need_to_loop to true

6) process the eventual contentSelector elements and/or the @suppressFromResult attributes on the templates that have matching items/relationships in the response to remove or pair down items and relationships as requested
7) package the resulting items and relationships in a way that conforms to the CMDBf response message format (including putting each item in the <nodes> element with the appropriate @templateId attribute and putting each relationship in the <edges> element with the appropriate @templateId).
8) replace all the temporary template ids (from step 2) that appear in templateId attributes in the response with the original ids of the items and template based on the records that were kept in step 2.

Just to clarify things, what I do in step 2 is simply make explicit all the itemTemplates and relationshipTemplates that are made implicit by the depthLimit element, so that we can provide with a simpler algorithm after that assumes that all relationshipTemplate correspond to direct relationships (no intermediary). And in step 8 I hide the fact that this took place.

28
Oct
2007

Review of the CMDBf specification version 1.0

by William Vambenepe

Having read the recently released CMDBf 1.0 specification over the weekend, I see several improvements since 0.95, including:

  • the introduction of depthLimit
  • the lastModified metadata element
  • the ability to specify more than one instanceId in a template
  • the ability to advertise what parts of the specification you implement
  • the definition of faults

But while 1.0 is more complete than 0.95, I think it makes it harder to achieve interoperability. Here are the main friction points for interop:

New role for XPath

The xpathExpression element (which replaces xpath1Selector) changes in two very important ways. First, rather than being limited to XPath 1.0, it now also allows XPath 2.0. Support for this is a lot harder to achieve for people who don’t use XML as the backend format for their data. Considering the current state of adoption of XPath 2.0 and the low level of XML complexity exposed by most CMDB models, I don’t think it was opportune to bring this into CMDBf yet. And my guess is that most implementations will stay away from this. But there is a second change, less obvious but even more problematic. XPath is not just another constraint mechanism for a CMDBf template anymore, one that returns a boolean result indicating whether the instance meets the constraint or not, as it used to be in 0.95. It is now an alternative selection and filtering mechanism that lives in parallel to all the other elements in a template (and can’t mix with them). Overall, I think this change goes too far in the direction of turning a shared agreement to exchange data in XML into an assumption that the internal data models are all based on XML. And the killer with regards to interoperability is that the specification says nothing about how the resulting node sets are serialized in the response. There may be a serialization for the XPath 2.0 model, but there is no such thing for XPath 1.0 and I don’t see in the current state of the specification how two implementations have any chance to interoperate when using this feature.

Introduction of linkDepth

As I mentioned earlier, linkDepth is a very useful addition (even though it pales in comparison to the inferencing capabilities that could have been derived from basing CMDBf on RDF). But it is also a complicated feature. The intermediateItemTemplate attribute is a good re-use of the existing plumbing, but it needs at least a detailed example. I trust that the group will generate one once they’ve caught their breath from putting out the specification.

Service capability metadata

There is a new section (#6) to provide ways to describe what CMDBf features an implementation supports. But it is a very granular representation. Basically, for every feature you can describe if you support it or not. So someone may describe that they support everything inside propertyValue, except for the “like” operator. And someone else might support all the operators but not the caseSensitive modifier. That might be ok for human consumptions, but automated scenarios rely on pre-programmed queries and that is made very hard by all the possible combinations of options. What we need is a few well-defined profiles that people implement fully. Starting of course with a profile that rules out xpathExpression.

Record metadata

This new version introduces metadata on records. While recordId and lastModified are probably well understood and interoperably usable I am a bit more dubious about whether baselineId and snapshotId are going to be interoperable across vendors based on their limited description in the specification. The nice thing is that this metadata can not only be returned but also searched on. Well, at least that’s the intent. But this goes through the recordMetadata attribute on propertyValue which, while present in the pseudo-schema, is missing in the XSD…

The contentSelector element

This new element is more flexible that the propertySubsetDirective element that it replaces. In addition to specifying what properties you want returned it also allows you to specify that you only want certain record types and/or that you only want the record(s) that were used to satisfy constraints in the template. Those are nice additions, but the way the second part is implemented (through the use of the matchedRecords attribute) seems to assume that only one record in the instance was used to match all the constraints in the template. This is not necessarily the case, an instance can be selected by having different records match the different constraints in the template as long as it has at least one matching record per constraint (line 765 says “the item satisfies all the constraints”, not “a record of the item satisfies all the constraints” and you can also see this in the example in section 4.2 where the records mentioned on lines 637 and 639 don’t have to be the same). So do you return all records that have a role in matching the template, or only those (if there is any) that matches all the constraints on their own as the text seems to imply? And if several record combinations inside an instance can be used to match the constraints in a template, do I return all of them or can I just pick any subset that matches? Also, how can I say that I want all records that established the template match, independently of their type? There doesn’t seem to be a way to do this, or is it by putting a contentSelector element with no child element and the matchedRecords attribute set to false? There won’t be much interoperability on this feature until all this is clarified.

Relationships as items

A major change between 0.95 and 1.0 is that now a relationship can match an itemTemplate. For example, if you ask for all items that were modified during the last 24 hours you will get all the items and all the relationships that meet that criteria while in the previous version you’d have to explicitly request the relationships with a relationshipTemplate if you wanted to get them too). There is a good case to be made for either view and the one that works best largely depends on your backend implementation technology (RDF, objects, SQL, CIM…). But the important thing is for the spec to be clear and on this point I think the change wasn’t made explicit enough in the query section of the specification. If Van hadn’t called my attention to this on his blog, I would have missed this important change.

Security boilerplate

There is a person at IBM (probably located in a well-stoked underground bunker in upstate NY) who has instilled the fear of god in all IBM employees (at least all those who author publicly available specifications) and forces them to include a boilerplate “security considerations” section everywhere. I have co-authored several documents with IBM employees and it never fails, even thought it doesn’t add anything useful to the specification. You should see the look of fear on the face of the IBM employees when someone else suggests doing without it. We somehow managed to sneak one such slimmer specification past the IBMers with CMDBf 0.95 but I see that this has been “corrected” in 1.0. I hope that whatever painful punishment Scott, Jacob, Andrew and Mark (or their families and pets) were subjected to in the process by the IBM security ogre wasn’t too cruel. Sure, this doesn’t really impact interoperability, but now that I don’t work for a company that makes money from ink anymore, I have even less patience for this bloating.

OK, that’s enough back seat driving for now. Hopefully the standards group that will take over the specification will address all these questions. In the context of the entire specification, these are pretty small issues and mostly easy to fix. And the CMDBf group can go on to address the hard issues of federation (including security-related issues that abound in this field if one really wants to tackle them). The current specification is a useful graph-oriented query language that is a good match for CMDB data. But it’s really just a query language (plus a simple registration system).

[UPDATE: while updating the CMDBf query algorithm, I noticed another small error: maxIntermediateItems is an attribute in the pseudo-schema but an element in the schema. Something else to fix in the next version.]

25
Oct
2007

CMDBf 1.0 specification released

by William Vambenepe

The CMDBf committee has just released version 1.0 of the specification. Van Wiles has an overview of the changes between 0.95 and 1.0. I left HP soon after 0.95 was released and that’s when my participation in CMDBf ended, so Van’s summary is very useful to me. The changes he lists are not surprising and some of them already existed in draft form before 0.95 publication. I need to spend some intimate time with the specification to review the changes to the template mechanism in more details. Some of the changes have the potential to make the specification quite a bit harder to implement. This is especially the case for the introduction of “depthLimit” (but it’s probably a needed feature anyway). And the fact that relationships can now match item selectors will make things either easier or harder to implement, depending on your implementation choice (e.g. straight-to-SQL/XML or through an OO or RDF model). Congrats to the group. We should soon hear about submission for standardization.

03
Aug
2007

Tutorial and pseudo-algorithm for CMDBF Query operation

by William Vambenepe

[UPDATE: an updated version of the algorithm that complies to version 1.0 of the specification (and not 0.95 as in this post) is now available]

The CMDBF Query operation (section 4 of the CMDBF specification) quickly becomes very intuitive to use, but it can first look a little strange to people used to SQL-style queries, because of its graph-based nature. I hope the normative text and the examples in the spec mitigate this. But just in case, here is some additional information that doesn’t belong in the spec but can be useful. Think of it as a very first draft of a primer/tutorial about that Query interface.

The easiest way to think about this interface is to think graphically. Imagine that you’re not writing your query in XML, but instead creating it in a GUI. You want to find all Windows XP machines that are owned by someone in the marketing department. First you create a circle in the GUI that represents the machine (through a Visio-like drag-and-drop into the query composer window). You right-click on that circle and in the right-click menu you select the option called “type” and you set it to “computerSystem”. Then you right-click to select “add property constraint”. You enter “OS_Version” as the property name (if your GUI tools is any good it will present you with a list to choose from, based on the previously selected type) and “WindowsXP” as the value. Already you’ve created a query that selects all Windows XP machines. Not a bad start.

But you only want the machines that are owned by marketing people. So go ahead and create another circle to represent a person. Use similar right-click actions to set the type to “person” and to set the “department” property to “marketing”.

If you submit the query at this point, you’ll get a list of all Windows XP machines and all people in the marketing department. So, rather than reducing the result (by removing machines not owned by marketing people), you have expanded it (by adding records for the marketing people). Oops.

The next step is to create a relationship that constrains the machine to belong to someone in marketing. This is done very simply in our handy GUI tool by drawing an arrow that goes from the “person” circle to the “machine” circle. This requires that there be a relationship between the two. If we want to further ensure that this relationship is of type “owns” (and not “uses” for example), we do this by right-clicking on the arrow (like we do on circles), selecting “type” and setting its value to “owns”.

If we run the query now, we get the list of all Windows XP machines owned by marketing people. We also get the list of the marketing people who own these machines and we get the relationships between people and machines. So we now have want we wanted. But maybe a little more. Maybe we only care about the list of machines, we don’t want to retrieve all the data about the marketing people. As long as we know the machines are owned by marketing people, that’s all that we care about. We don’t need to know what specific person owns what specific machine. We could simply ignore the people and relationships in the response. Or we could enrich the query to specify that the people and relationship need not be returned (but they are still part of the query in the sense that they limit what machines get returned).We do this by right-clicking on the “person” circle, and selecting the “suppress” option. Similarly, select the “suppress” option on the relationship (the arrow) too.

This query will return a list of all Windows XP machines that are owned by someone in marketing, and nothing else.

Here is what the query could look like graphically (here I assume that the GUI tools represents the fact that the arrow and the “person” circle have the “suppress” option selected on them by turning their solid lines into dotted lines and their text into italics):

The most intuitive way to think about what happens when the query gets processed is that the program looks for all instances of the patterns described by the query. In other words, it tries to superimpose the requested graph everywhere on the graph of available data and selects all the instances where the requested graph “fits”.

What does the GUI tool do behind the scene to turn this query into the proper XML, as described by the spec?

For each circle, it creates an <itemTemplate> element. For each arrow, it creates a <relationshipTemplate> element and sets its <source> and <target> elements to the right item templates. For each constraint on a circle or arrow (i.e. when we set the type or when we set the value or a give property) it creates the appropriate selector and embeds it in the <itemTemplate> or <relationshipTemplate> that corresponds to this circle or arrow. Finally, it sets the @dropDirective attribute to “true” on all the <itemTemplate> and <relationshipTemplate> elements that corresponds to circles and arrows on which the “suppress” option was selected.

Here is what the resulting query looks like in XML:

<query xmlns="http://schemas.cmdbf.org/0-9-5/datamodel">
  <itemTemplate id="machine">
    <propertyValueSelector namespace="http://example.com/computerModel" localName="OS_Version">
      <equal>Windows XP</equal>
    </propertyValueSelector>
  <recordTypeSelector namespace="http://example.com/computerModel" localName="computerSystem"/>
  </itemTemplate>
  <itemTemplate id="person" dropDirective="true">
    <propertyValueSelector namespace="http://example.com/peopleModel" localName="department">
      <equal>marketing</equal>
    </propertyValueSelector>
    <recordTypeSelector namespace="http://example.com/peopleModel" localName="person"/>
  </itemTemplate>
  <relationshipTemplate id="administers" dropDirective="true">
    <recordTypeSelector namespace="http://example.com/computerModel" localName="owns"/>
    <source ref="person"/>
    <target ref="machine"/>
  </relationshipTemplate>
</query>

Note: like all query language, the actual query depends of course on the underlying model. In this example, I assumed that the OS version is represented as a property of the machine. More commonly, the OS will be a node of its own that has a relationship with the machine. So you’d have another circle for the OS. With a property constraint on that circle (version=”WindowsXP”) and a line representing a “runs” relationship between the machine circle and the OS circle. Similarly, “marketing” could be a node of its own that people have a relationship with, rather than just a property of each person. None of this changes the logic behind the Query operation.

Now, this is nice for the user of the query, but what about the poor developer who gets the 50-pages spec thrown on his/her desk and has 2 weeks to make sense of it and implement the server side of the query? I’ve said above that the program “tries to superimpose the requested graph everywhere on the graph of available data and selects all the instances where the requested graph fits” but that’s a lot easier to write as a sentence than to implement. So here is a pseudo-algorithm to help.

1) for each itemTemplate calculate the set of all items that obey all the selectors in the template. Call this the working set for the itemTemplate.
2) for each relationshipTemplate calculate the set of all relationships that obey all the selectors in the template. Call this the working set for the relationshipTemplate.
3) set need_to_loop = true
4) while (need_to_loop == true)

4.1) set need_to_loop = false
4.2) for each relationshipTemplate RT

4.2.1) let ITsource be the itemTemplate that is referenced as source by RT
4.2.2) let ITtarget be the itemTemplate that is referenced as target by RT
4.2.3) for each relationship R in the working set for RT

4.2.3.1) if the source of R is not in the working set for ITsource, then remove R from the RT working set
4.2.3.2) if the target of R is not in the working set for ITtarget, then remove R from the RT working set
4.2.3.3) if RT has a source/@minimum or a source/@maximum attribute

4.2.3.3.1) find the list L1 of all relationships in the working set for RT that have the same source as R
4.2.3.3.2) if RT has source/@minimum and the cardinality of L1 is less than this minimum then remove all relationships in L1 from the RT working set
4.2.3.3.3) if RT has source/@maximum and the cardinality of L1 is more than this maximum then remove all relationships in L1 from the RT working set

4.2.3.4) if RT has a target/@minimum or a target/@maximum attribute

4.2.3.4.1) find the list L2 of all relationships in the working set for RT that have the same target as R
4.2.3.4.2) if RT has target/@minimum and the cardinality of L2 is less than this minimum then remove all relationships in L2 from the RT working set
4.2.3.4.3) if RT has target/@maximum and the cardinality of L2 is more than this maximum then remove all relationships in L2 from the RT working set

4.3) for each itemTemplate IT

4.3.1) let sourceRTset be the set of all relationshipTemplates that references IT as its source
4.3.2) let targetRTset be the set of all relationshipTemplates that references IT as its target
4.3.3) for each item I in the IT working set

4.3.3.1) for each relationshipTemplate sourceRT in sourceRTset, if there is no relationship in the working set for sourceRT that uses I as its source, remove I from the IT working set and set need_to_loop to true
4.3.3.2) for each relationshipTemplate targetRT in targetRTset, if there is no relationship in the working set for targetRT that uses I as its source, remove I from the IT working set and set need_to_loop to true

5) process all directives (dropDirective or propertySubsetDirective) to remove or pair down items and relationships as requested
6) package the resulting items and relationships in a way that conforms to the CMDBF response message format (including putting each item in the <nodes> element with the appropriate @templateId attribute and putting each relationship in the <edges> element with the appropriate @templateId).

There are all kinds of optimizations possible here (like breaking out of loops once an instance has been removed, or not recalculating L1 and L2 over and over again for relationships in the same working set that share a source/target), but this is the most basic form or the algorithm. The goal is to illuminate the spec, not to provide an optimal implementation strategy.

In this post, I have focused on describing and illustrating the topological aspects of the query language. The other concepts that come into play are the Selector and the Directive mechanisms. But these are a lot more familiar to people used to SQL and I think they are sufficiently explained in the spec. So I have assumed here (in steps 1, 2 and 5 of the pseudo-algorithm) that they are well understood.

02
Aug
2007

First release of the CMDBF specification

by William Vambenepe

The CMDBF (CMDB Federation) group just released a first public draft of the specification. Here is a direct link to it (PDF, 1MB). That’s a very nice achievement for a group that was a bit slow to find its pace but has been very productive since the beginning of 2007. Having the interop test drive our efforts had a lot to do with it, this is an approach to repeat the next time around.

This spec will look a lot more familiar to people used to reading WS-* specs than to people used to reading ITIL manuals. The concepts and use cases are (hopefully) consistent with ITIL, but the meat of the spec is about defining interoperable SOAP-based message exchanges that realize these use cases. The spec is about defining SOAP payloads, not IT management best practices. Please adjust your expectations accordingly and you’ll like the spec a lot more.

The most useful and important part (in my mind at least), is the definition of the Query service (section 4). This is used in many interactions. It is used by clients to query a CMDB that federates many MDRs (Management Data Repositories). It is used by the clients to go interact directly with the MDRs is they choose to. And it is used by the federating CMDB to retrieve data from the MDRs. Even in the more static scenarios, in which data is replicated from the MDRs into the CMDB (instead of true federation with no replication), the Query service is still the way for clients to access federated data from the CMDB.

So, yet another query language? Indeed. But one that natively supports concepts that are key to the kind of queries most useful for CMDB scenarios, namely relationships traversal and types. This is a topological query language. I hope the simple example in section 4.2 gives a good example of what this means.

Neither SQL nor XPath/XQuery has this topology-friendly approach (which is not to say that you can’t create useful queries on CMDB data with these query languages). On the other hand, there is one query language that is inherently relationship-oriented, that has native support for the notion of class and that has received a lot more attention, interop testing and implementation experience than our effort. One that I would have loved for us to leverage in CMDBF. It’s SPARQL. But semantic web technologies seem once again to be doomed by the perception that they are too much “out there” despite all the efforts of its proponents to make them connect with XML and other non-RDF views of the world.

Final caveat, this is a first draft. It is known to be incomplete (you’ll find text boxes that describe known gaps) and not all features in the spec were tested at the interop. We need more interop, review and development before it is robust. And most importantly, a lot of the difficult aspects of federation aren’t sufficiently addressed (reconciliation, model differences, source tracing, administrative metadata…) But it is at a point where we think it gives a good idea of how we are approaching the problem.

Equipped with this foreword, I wish you a pleasant read.

25
Jun
2007

CMDBF interoperability testing (alpha edition)

by William Vambenepe

Last week, a bunch of us from the CMDBF author companies got together in a room for our first interoperability testing event. It was based on a subset of the spec. As usual with these kinds of events, the first hurdle was to get the network setup right (we had a mix of test endpoints running on remote servers and on our laptops; getting all laptops to talk to one another on a local network was easy; getting them all to talk to the remote endpoints over the internet was easy too; but getting both at the same time took a bit of work).

Once this was taken care of, the interop tests went pretty smoothly. A few problems were found but they were fixed on the fly and by the end we had happy MDRs (Management Data Repositories) talking to happy CMDBs who themselves were accessed by happy client applications. All this using the CMDBF-defined query and update interfaces.

Next steps are to update the spec with the lessons from the interop and to complete it with a few additional features that we put out of scope for the interop. Stay tuned.

11
Jun
2007

Standards are good for customers… right?

by William Vambenepe

Standards are good for customers. They avoid vendor lock-in. They protect the customer’s investment. Demanding standards compliance is a tool customers have to defend their interests when dealing with vendors. Right?

Well, in general yes. Except when standards become tools for vendors to attempt to confuse customers.

In the recent past, I have indirectly witnessed vendors liberally using the “standard” word and making claims of compliance with (and touting the need to conform to) specifications…

  • that have barely been submitted for standardization (SML),
  • that haven’t even been published in any form (CMDBF), or
  • that don’t even exist as a draft (CML - no link available, and for a reason).

Doesn’t something sound fishy when the logic goes through such self-negating statements as: “standards are good for you because they give you a choice of vendor. And we are the only vendor who supports standard X so you need to buy from us.” Especially when if it was true that the vendor in question implemented standard X, then it would not be their software that I would want to buy from them but their time machine.

All this doesn’t negate the fundamental usefulness of standards. And I don’t mean to attack the three specifications listed above either. They all have a very good potential to turn out to be useful. HP is fully engaged in the creation of all three (I am personally involved in authoring them, which is generally why wind of these exaggerated vendor claims eventually get back to me).

Vendors who are used to creating proprietary environments haven’t all changed their mind. They’ve sometimes just changed their rhetoric and updated their practices to play the standards game (changing the game itself in the process, and often not for the better). Over-eagerness should always arouse suspicion.

16
Feb
2007

CMDB Federation white paper released

by William Vambenepe

As reported earlier, some of movers and shakers in IT management got together last year to standardize the way to federate configuration repositories. Since then the only link available has been to a press release, which is embarrassing to say the least. Well, cmdbf.org recently came up and it is now serving a white paper that describes in more details the vision that we (the companies involved) are pursuing by this collaboration.

By linking to them from the same page, we have (by some definition) successfully federated the press release and the white paper. Way to go!