----- Original Message -----
> From: "Oved Ourfalli" <ov...@redhat.com>
> To: "Saggi Mizrahi" <smizr...@redhat.com>
> Cc: dc...@redhat.com, "VDSM Project Development" 
> <vdsm-devel@lists.fedorahosted.org>
> Sent: Tuesday, October 8, 2013 4:15:22 PM
> Subject: Re: [vdsm] vdsm sync meeting - October 7th 2013
> 
> 
> 
> ----- Original Message -----
> > From: "Saggi Mizrahi" <smizr...@redhat.com>
> > To: "Oved Ourfalli" <ov...@redhat.com>
> > Cc: dc...@redhat.com, "VDSM Project Development"
> > <vdsm-devel@lists.fedorahosted.org>
> > Sent: Tuesday, October 8, 2013 4:08:12 PM
> > Subject: Re: [vdsm] vdsm sync meeting - October 7th 2013
> > 
> > 
> > 
> > ----- Original Message -----
> > > From: "Oved Ourfalli" <ov...@redhat.com>
> > > To: "Saggi Mizrahi" <smizr...@redhat.com>
> > > Cc: "Dan Kenigsberg" <dan...@redhat.com>, dc...@redhat.com, "VDSM Project
> > > Development"
> > > <vdsm-devel@lists.fedorahosted.org>
> > > Sent: Tuesday, October 8, 2013 11:42:23 AM
> > > Subject: Re: [vdsm] vdsm sync meeting - October 7th 2013
> > > 
> > > 
> > > 
> > > ----- Original Message -----
> > > > From: "Saggi Mizrahi" <smizr...@redhat.com>
> > > > To: "Dan Kenigsberg" <dan...@redhat.com>
> > > > Cc: dc...@redhat.com, "VDSM Project Development"
> > > > <vdsm-devel@lists.fedorahosted.org>
> > > > Sent: Monday, October 7, 2013 5:42:54 PM
> > > > Subject: Re: [vdsm] vdsm sync meeting - October 7th 2013
> > > > 
> > > > 
> > > > 
> > > > ----- Original Message -----
> > > > > From: "Dan Kenigsberg" <dan...@redhat.com>
> > > > > To: "VDSM Project Development" <vdsm-devel@lists.fedorahosted.org>,
> > > > > dc...@redhat.com
> > > > > Sent: Monday, October 7, 2013 5:25:22 PM
> > > > > Subject: [vdsm] vdsm sync meeting - October 7th 2013
> > > > > 
> > > > > We had an unpleasant talk, hampered by statics and disconnection on
> > > > > danken's side. Beyond the noises I've managed to recognize Yaniv,
> > > > > Toni,
> > > > > Douglas, Danken, Ayal, Timothy, Yeela and Mooli. We've managed to
> > > > > discuss:
> > > > > 
> > > > > - vdsm-4.13.0 is tagged, with a know selinux issue on el6. Expect a
> > > > > new
> > > > >   seliux-policy solving it any time soon.
> > > > > 
> > > > > - All bugfixes should be backported to ovirt-3.3, so that we have a
> > > > >   stable and comfortable vdsm in ovirt-3.3.1. Risky changes and new
> > > > >   features should remain in master IMO.
> > > > > 
> > > > > - We incorporated a glusterfs requirement breaking rpm installaiton
> > > > > for
> > > > >   people. We should avoid that by posters notifying reviewers more
> > > > >   prominently and by having
> > > > >   http://jenkins.ovirt.org/job/vdsm_install_rpm_sanity_gerrit/
> > > > >   run on every patch that touches vdsm.spec.in.
> > > > > 
> > > > >   David, could you make the adjustment to the job?
> > > > > 
> > > > > - We discussed feature negotiation: Toni and Dan liked the idea of
> > > > >   having vdsm expose a feature flags, to make it easier on Engine to
> > > > >   check if a certain feature is supported.
> > > > > 
> > > > >   Ayal argues that this is useful only for capabilities that depend
> > > > >   on
> > > > >   existence on lower level components. Sees little value in fine
> > > > >   feature granularity on vdsm side - versions is enough.
> > > > > 
> > > 
> > > Versions might not be enough here, as some features might be supported by
> > > VDSM version X, but not when it is installed under operating system Y.
> > > IMO, VDSM should reflect that when reporting the features.
> > > 
> > > > >   So the disputed question is only how many feature flags we should
> > > > >   have, and when to set them: statically or based on negotiation with
> > > > >   kernel/libvirt/gluster/what not.
> > > > I already voiced my reservation over the entire concept
> > > > of "feature flags".
> > > > Proposing we only move to specific introspective verbs
> > > > maintained in the subsystem.
> > > > 
> > > > Have vdsm.getAvailableStorageDomainTypes() ['gluster']
> > > > 
> > > > instead of vdsm.getFeatures()
> > > > ['storagetype/gluster']
> > > > 
> > > > It allows for much higher level of flexibility as the aforementioned
> > > > verb
> > > > can also return other information about the domain type:
> > > > For example returning each domain type with parameter information:
> > > > {'nfs': {'connect_params': [
> > > >         {'name': 'timeout',
> > > >          'type': 'int',
> > > >          'range': [0, 99],
> > > >          'desc': 'Sets the timeout',
> > > > 
> > > > So even parameters can potentially be introspected.
> > > > 
> > > 
> > > IMO it is great to have a verb per "domain" (e.g. network, storage, virt,
> > > etc.), as it allows getting deeper information about features.
> > > However, it does not conflict with having a single general getFeatures
> > > verb.
> > > Such a verb can be useful cases in which you don't really need more
> > > information, for example in establishing a feature negotiation between
> > > the
> > > engine and VDSM.
> > No one is talking about feature negotiation. It's feature reporting.
> 
> You're right. My bad. Feature reporting is the right terminology here.
> 
> 
> > And all I'm saying is that having a verb reporting unrelated things in
> > unrelated formats is usually a bad idea.
> > 
> > How would features be represented strings? fqdn? objects of different
> > types?
> > If it's a string how would the user know how features depends on each
> > other.
> > How granular should this be? How do we change granularity in the future?
> > 
> > We must have verbs with clear scope. Anyone can tell what
> > GetServerConnectionTypes()
> > needs to return. We know what it's granularity is. We know how it relates
> > to
> > other things. We know what flows need to check it and how it might effect
> > them.
> > 
> > I have no idea what getFeatures() even means.
> > 
> 
> The users don't have to directly look at the features the host returns.
> The engine can have a mapping between features VDSM reports, and "user
> features" - features that do have a meaning to the user.
> The mapping will probably be one-to-many in most cases.
Seems like a huge layering violation.
The engine should keep this information contextually and not in a global
list.
VDSM shouldn't go inspecting itself to produce a list for the engine.
This is what I was talking about granularity and grouping. It's easier
for the engine to just look at things in and out of VDSM and compose the
on it's own. This way if the engine decides to compose "features" in a
different way VDSM doesn't need to change.

I think the real conversation should be about what introspective verbs are
missing and how should we add them.
> 
> > 
> > > If you find out that a specific feature is supported, and
> > > you would like to get more details, such as parameter information, you
> > > would
> > > query specifically for that.
> > > 
> > > > > 
> > > > > - Unified network persistence patches are being merged into master
> > > > > 
> > > > > - Timothy is working on fixing
> > > > >   
> > > > > http://jenkins.ovirt.org/job/vdsm_verify_error_codes/lastBuild/console
> > > > >   (hopefully by introducing the new error codes to Engine)
> > > > > 
> > > > > I was dropped from the call, so please append with stuff that I've
> > > > > missed. Sorry for the noise!
> > > > > 
> > > > > Dan.
> > > > > _______________________________________________
> > > > > vdsm-devel mailing list
> > > > > vdsm-devel@lists.fedorahosted.org
> > > > > https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel
> > > > > 
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> > > > 
> > > 
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