Resource Type versioning

John Mazzitelli mazz at redhat.com
Fri Dec 19 14:33:52 UTC 2014


2 may be a stupid property, but it has very low overhead, doesn't affect the entire system, and only affects one resource type.

I vote for 2. stupid property to fix a stupid bug :)

----- Original Message -----
> Hello,
> 
> I'd like to ask for advice/recommendation. I am trying to fix
> https://bugzilla.redhat.com/show_bug.cgi?id=1173479 and sofar I came up
> with 3 solutions - and I don't like any of those (what a bad day today).
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1173479 - we introduced 2 new
> pluginConfiguration properties (which are required and have default
> values), but we forgot to add code to resourceUpgrade facet
> implementation, that detects those 2 props on existing resources. Now,
> after upgrades to 4.13 it's too late for writing the resourceUpgrade code.
> The code would have either to
> 
> 1) try to detect those 2 properties on every agent start - because it is
> not able to distinguish between older/newer resource. Resources imported
> before upgrade have default values, and resources after upgrade have
> correct values. Plugin code would have to literally detect both values at
> agent start.
> or
> 
> 2) add another boolean property foo that would denote if a resource was
> discovered before or after upgrade (those before will get upgraded and we
> detect our 2 properties and foo is set to true (=upgraded))
> 
> 
> 3) introduce resource type version: extend plugin descriptor with optional
> numeric attribute typeVersion. This typeVersion would help plugins in
> resourceUpgrade code to know whether to run or not. typeVersion would have
> to be stored in resource as well and upgradeCode would have to set the
> version to latest and greatest in case the resource was upgraded (maybe
> this could go to agent code)
> 
> I don't like any of above solutions
> 
> 1) potential slowdown of agent start (especially if it is going to hit
> resources being intentionally down)
> 2) stupid property
> 3) maybe an overhead to enrich all resources / resource types just because
> of this type of bug. But this is my canditate.
> 
> I'd be thankful for any comments.
> 
> 
> --
> Libor Zoubek
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> 


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