10:41 a.m.
On 03/18/2013 12:59 PM, Mike Kolesnik wrote:
----- Original Message -----
> Hi all,
>
> The current mechanism in oVirt to check whether a feature is
> supported
> in a particular compatibility version is to use the FeatureSupported
> class. e.g.
>
> FeatureSupported.networkLinking(getVm().getVdsGroupCompatibilityVersion())
>
> Checks whether the "network linking" feature is supported for the the
> VM's cluster compatibility version. This internally checks whether
> the
> value of the corresponding config (NetworkLinkingSupported) for the
> given compatibility version is true/false.
>
> I'm not sure if this is a good idea, since a feature is typically
> supported "from" a particular version. E.g. Gluster support was
> introduced in 3.1, and it continues to be available in all subsequent
> versions. So I see no point in adding configuration for every version
> indicating whether the feature is supported in that version or not. I
> suggest to use either of the following options:
You can "merge" the configs into a single config when older versions go out of
the supported versions for the system.
i.e. in 4.0 you can have upgrade script that merges all GlusterFeatureSupported to one
entry instead of several.
> 1) Instead of using a boolean config for each version, use a single
> string config that indicates the "supported from" version e.g.
> GlusterSupportedFrom = 3.1. There could be rare cases where a
> feature,
> for some reason, is removed in some release. In such cases, we could
> use
> one additional config for the "supported to" version.
>
> 2) Continue with the boolean approach, but do not have entries for
> every
> version; rather make use of the "default value" for majority of
> cases,
> and add the explicit version mapping for the minority e.g.
> GlusterSupported = true by default, and false in case of 3.0 (only
> one
> config required for 3.0)
I'm not sure why we would want to complicate this simple mechanism?
Is there much to gain?
I think option 1 suggested above is simpler - to implement as well as to
understand.
Let me give you an example of why I don't like current mechanism. I
introduce a version check for a feature that was introduced in 3.1. I'm
being asked now to add three entries in config
3.0 - false
3.1 - true
3.2 - true
It will also mean that when 3.3 goes out, someone has to make sure that
another entry is added for 3.3-true. I think it is not logical as well
as scalable if you have more versions. And it sounds far more complex
(to maintain) than just having
<Feature>SupportedFrom = 3.1
So I would like to know if there are any objections to my proposal. I
intend to use this for at least the gluster related features.
> Thoughts?
>
> Regards,
> Shireesh
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