[ovirt-devel] hosted-engine setup/migration features for 3.6

[Yedidyah Bar David]

----- Original Message -----
> From: "Bob Doolittle" <bob at doolittle.us.com>
> To: "Yedidyah Bar David" <didi at redhat.com>
> Sent: Wednesday, December 3, 2014 2:50:12 PM
> Subject: Re: [ovirt-devel] hosted-engine setup/migration features for 3.6
> 
> Another issue with that page is that it assumes a remote database. I am not
> sure what percentage of cases have remote databases but clearly many
> (most?) do not, since that's not default behavior.

I agree.

> So that page definitely
> needs attention. See:
> https://bugzilla.redhat.com/show_bug.cgi?id=1099995

Indeed. Note that this isn't specific to hosted-engine, it's the same for
any migration using engine-backup to backup/restore, therefore there is
a link to its page in the top, where this is more detailed. We also have
a bug [3] to automate this.

[3] https://bugzilla.redhat.com/show_bug.cgi?id=1064503

> https://bugzilla.redhat.com/show_bug.cgi?id=1099998
> 
> Some of us have wanted to disable global maintenance upon bootup by adding
> a systemd service on Fedora 20 (since you must enable global maintenance to
> shut it down cleanly), and have found it impossible to create the necessary
> systemd dependencies. It seems that (at least with 3.4) hosted-engine
> --set-maintenance --mode=none will return an error for several seconds
> after all other services have started and it's not clear what can be waited
> upon in order to issue the command with assurance it will complete
> successfully. This isn't strictly a setup/migration issue but it is an
> issue with setting up a desired configuration with hosted-engine. The way
> to reproduce this is simply to wait until gdm-greeter displays the login
> prompt, ssh into the system and execute hosted-engine --set-maintenance
> --mode=none and observe the error. Or create a systemd service that depends
> upon (waits for) the latest-possible service, try executing the command
> there, and observe the error. Ideally there would be some external
> observable event which a systemd service could depend upon, when
> hosted-engine is ready to do its thing.

Adding Jiri for that. Do you have an open bug?

Thanks,

> 
> Regards,
>     Bob
> 
> 
> On Wed, Dec 3, 2014 at 2:59 AM, Yedidyah Bar David <didi at redhat.com> wrote:
> 
> > Hi all,
> >
> > We already have quite a lot of open ovirt-hosted-engine-setup bugs for 3.6
> > [1].
> >
> > Yesterday I tried helping someone on irc who planned to migrate to
> > hosted-engine
> > manually, and without knowing (so it seems) that such a feature exists. He
> > had
> > an engine set up on a physical host, prepared a VM for it, and asked about
> > migrating
> > the engine to the VM. In principle this works, but the final result will
> > be a
> > hosted-engine, where the engine manages a VM the runs itself, without
> > knowing it,
> > and without HA.
> >
> > The current recommended migration flow is described in [2]. This page is
> > perhaps
> > a bit outdated, perhaps missing some details etc., but principally works.
> > The main
> > issue with it, AFAICT after discussing this a bit with few people, is that
> > it
> > requires a new clean host.
> >
> > I'd like to hear what people here think about such and similar flows.
> >
> > If you already had an engine and migrated to hosted-engine, what was good,
> > what
> > was bad, what would you like to change?
> >
> > If you plan such a migration, what do you find missing currently?
> >
> > [1] http://red.ht/1vle8Vv
> > [2] http://www.ovirt.org/Migrate_to_Hosted_Engine
> >
> > Best,
> > --
> > Didi
> > _______________________________________________
> > Devel mailing list
> > Devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/devel
> >
> 

-- 
Didi