Re: [Engine-devel] Bug 1076530 – engine shouldn't kill the vds running the VM with the hosted engine

From: "Doron Fediuck" <dfediuck(a)redhat.com&gt; To: "Sandro Bonazzola" <sbonazzo(a)redhat.com&gt; Cc: "Yedidyah Bar David" <didi(a)redhat.com&gt;, "engine-devel" <engine-devel(a)ovirt.org&gt; Sent: Monday, March 17, 2014 10:08:31 AM Subject: Re: [Engine-devel] Bug 1076530 – engine shouldn't kill the vds running the VM with the hosted engine ----- Original Message ----- > From: "Sandro Bonazzola" <sbonazzo(a)redhat.com&gt; > To: "Yedidyah Bar David" <didi(a)redhat.com&gt;, "Doron Fediuck" > <dfediuck(a)redhat.com&gt; > Cc: "engine-devel" <engine-devel(a)ovirt.org&gt; > Sent: Monday, March 17, 2014 9:11:20 AM > Subject: Re: [Engine-devel] Bug 1076530 – engine shouldn't kill the vds > running the VM with the hosted engine > > Il 16/03/2014 11:59, Yedidyah Bar David ha scritto: > > > > > > ----- Original Message ----- > >> From: "Doron Fediuck" <dfediuck(a)redhat.com&gt; > >> To: "Yedidyah Bar David" <didi(a)redhat.com&gt; > >> Cc: "Sandro Bonazzola" <sbonazzo(a)redhat.com&gt;, "Jiri Moskovcak" > >> <jmoskovc(a)redhat.com&gt;, "engine-devel" > >> <engine-devel(a)ovirt.org&gt; > >> Sent: Sunday, March 16, 2014 12:47:43 PM > >> Subject: Re: Bug 1076530 – engine shouldn't kill the vds running the VM > >> with the hosted engine > >> > >> > >> > >> ----- Original Message ----- > >>> From: "Yedidyah Bar David" <didi(a)redhat.com&gt; > >>> To: "Doron Fediuck" <dfediuck(a)redhat.com&gt; > >>> Cc: "Sandro Bonazzola" <sbonazzo(a)redhat.com&gt;, "Jiri Moskovcak" > >>> <jmoskovc(a)redhat.com&gt; > >>> Sent: Sunday, March 16, 2014 12:28:27 PM > >>> Subject: Re: Bug 1076530 – engine shouldn't kill the vds running the VM > >>> with the hosted engine > >>> > >>> Might be better to discuss this on bugzilla. > >>> > >> Bugzilla is not a mailing list. Moving to engine-devel. > >> > >>> ----- Original Message ----- > >>>> From: "Doron Fediuck" <dfediuck(a)redhat.com&gt; > >>>> To: "Sandro Bonazzola" <sbonazzo(a)redhat.com&gt; > >>>> Cc: "Yedidyah Bar David" <didi(a)redhat.com&gt;, "Jiri Moskovcak" > >>>> <jmoskovc(a)redhat.com&gt; > >>>> Sent: Sunday, March 16, 2014 12:01:51 PM > >>>> Subject: Bug 1076530 – engine shouldn't kill the vds running the VM > >>>> with > >>>> the hosted engine > >>>> > >>>> https://bugzilla.redhat.com/show_bug.cgi?id=1076530 > >>>> > >>>> Sandro, > >>>> I think this would be solved by a better validation during setup / > >>>> deployment. > >>> > >>> This can't be done during Validation in the otopi sense of the word. > >>> At that point the engine does not exist yet and so we can't know what > >>> versions it supports etc. > >>> > >> Why not? > >> You have the vdsm supported versions in a file (dsaversion IIRC) > >> and you should be able to get the relevant engine info before or > >> after deploying the DB. > > > > The VM does not exist yet at that point. How can you know what the user > > will install on it? You can tell them what they *should* install - e.g. > > "The highest compatibility version supported by this host is 3.4, you > > should install a 3.4 engine inside the engine VM". But we can't know what > > the user actually did until after we connect to the installed and working > > engine. > > > >> > >>> It might be possible (didn't check) to check the versions right before > >>> trying to add the host to the cluster. This means we do not want to > >>> abort (as we can do during Validation if something does not pass it). > >>> What can we do? Perhaps offer a few options: > >>> 1. Do abort (will do mostly what happens today) > >>> 2. Let the user try to manually fix, probably by trying to change > >>> the compatibility version of the cluster, and then try adding the > >>> host again > >>> 3. Try to fix ourselves (same) and try adding again > >>> 4. Best would be to someone upgrade libvirt and reconfigure vdsm. > >>> Not sure that's easy or even possible at this stage, where VM is > >>> running and we do not want to loose it. > > We can check VDSM caps in late setup / customization and abort if cluster > compatibility is not 3.4. > I'm not sure that VDSM 3.3 is enough for running hosted engine. > > We can warn the user about the minimum version of oVirt engine that must be > installed inside the VM and > after that we can check oVirt engine cluster compatibility and refuse to > continue until the cluster > have a correct support level. This will require manual changes like > upgrading > the engine in the VM > or fix cluster compatibility level if we find an invalid value. > If we can assist the user with fixing cluster compatibility level to avoid a malformed end result this is the solution I'd go with. In this way the user will always get a working setup, with the relevant information. ie- something like:

Current engine settings does not support your vdsm version please select how you wish to proceed: (1) Manually upgrade vdsm

(2) Lower cluster compatibility to support your installed vdsm (3) Abort Option (2) should do a simple db update to make sure the user has a running setup.