Re: [Xen-cim] InstanceID property

[Gareth S Bestor <bestor@xxxxxxxxxx>]

To be strictly conformant with the DMTF, yes, at some point we should use "proper" InstanceIDs everywhere. However, as you found out the hard way :-), this key property is used in a number of place to match the endpoints of various associations with each other, as well as make calls down into libxm/libvirt to pass in the desired DomU name. So changing the InstanceId format will require making some appropriate changes in a few other places in the provider code where it is used to make correspondences.

>From the CIM_SettingData mof:

----------------------
Key
string InstanceID ;
Within the scope of the instantiating Namespace, InstanceID opaquely and uniquely identifies an instance of this class. To ensure uniqueness within the NameSpace, the value of InstanceID should be constructed using the following 'preferred' algorithm:
<OrgID>:<LocalID>
Where <OrgID> and <LocalID> are separated by a colon (:), and where <OrgID> must include a copyrighted, trademarked, or otherwise unique name that is owned by the business entity that is creating or defining the InstanceID or that is a registered ID assigned to the business entity by a recognized global authority. (This requirement is similar to the <Schema Name>_<Class Name> structure of Schema class names.) In addition, to ensure uniqueness, <OrgID> must not contain a colon (:). When using this algorithm, the first colon to appear in InstanceID must appear between <OrgID> and <LocalID>.
<LocalID> is chosen by the business entity and should not be reused to identify different underlying (real-world) elements. If the above 'preferred' algorithm is not used, the defining entity must assure that the resulting InstanceID is not reused across any InstanceIDs produced by this or other providers for the NameSpace of this instance.
For DMTF-defined instances, the 'preferred' algorithm must be used with the <OrgID> set to CIM.
------------------------

Note "... should be constructed using the following 'preferred' algorithm"

That said, I'm not sure how strictly this "preferred" algorithm is followed in the industry, so I dont think this is necessarily a high-priority fix right now (eg we probably have bigger fish to fry) but something that does need to be done at some point.

- Gareth

Dr. Gareth S. Bestor
IBM Linux Technology Center
M/S DES2-01
15300 SW Koll Parkway, Beaverton, OR 97006
503-578-3186, T/L 775-3186, Fax 503-578-3186

Jim Fehlig <jfehlig@xxxxxxxxxx>

Jim Fehlig <jfehlig@xxxxxxxxxx>
Sent by: xen-cim-bounces@xxxxxxxxxxxxxxxxxxx

05/31/06 02:46 PM

To	xen-cim@xxxxxxxxxxxxxxxxxxx
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Subject	[Xen-cim] InstanceID property

CIM_SettingData contains the key property InstanceID, which should be 
constructed with the "preferred" algorithm described in the mof.  
Basically InstanceID should be "<OrgID>:<LocalID>".  Should we move to 
the preferred form of InstanceID?

Several weeks back I changed the SettingData classes to use the 
algorithm but did not consider how this affected some associations.  
Found one such case during testing today and decided to ask whether we 
want to support the preferred algorithm or drop back to the original 
code that just provided <LocalID>.  What do we want to use for OrgID if 
supporting the preferred algorithm?  The current code uses "Xen:"

Jim

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