Re: [ovirt-users] how to prepare for an engine re-install
----- Original Message -----
From: "Robert Story" <rstory(a)tislabs.com>
To: Users(a)ovirt.org
Sent: Wednesday, February 18, 2015 5:12:40 PM
Subject: [ovirt-users] how to prepare for an engine re-install
I'm running ovirt (engine 3.4.0-1.el6) on a dedicated engine machine with a
degraded raid array. This has caused the root filesystem to go read-only,
and the engine crashed. I can restart the engine, but after doing so, the
web page just loads a blank page. All nodes and VMs seem to be fine, I just
can't manage them via oVirt.
Because I'm offsite, my recovery option is likely limited to a reinstall of
the OS and ovirt. I'm hoping for some pointers on what I can do in advance
to minimize the pain of this transition.
- Am I going to be able to recover without having to shut down VMs,
exporting and importing?
Perhaps, depends on your plan
- what directories should I back up?
If at all possible, you should try engine-backup. I guess it will fail if
the fs is read-only, because postgres will not start and engine-backup
uses it.
You might get by with copying the stuff engine-backup does (search for
BACKUP_PATHS in its start), and also a cold copy of the database - all
of /var/lib/pgsql/data .
Try copying the db to another machine and 'service postgresql start'.
If it works, and you can connect to the db, full recovery will probably
work.
- when I reinstall, should I upgrade and install 3.5.1, or first install
3.4, get it working, and then think about upgrading?
I'd separate them. Reinstall with exact same version if possible - not sure
you can find 3.4.0 on the yum repo, perhaps you can find somewhere in your
cache the version you use, or something like that - then upgrade when all is
quiet.
- Is it possible/recommended/crazy to migrate to a hosted engine instead
of a dedicated machine?
In principle should be possible.
So I want to prepare for the worst before I try a reboot.
If it's currently read-only, why not simply copy all of it somewhere? Then
if a reboot kills it, you still have the copy to try and recover from.
If I'm lucky, the
reboot will at least come up with a writable filesystem, and I won't need to
re-install. If it doesn't come up, I want to be as ready as possible for
the reinstall.
Any hints and/or tips appreciated..
If at all possible, practice on a test system before trying live :-)
See [1] for an overview of a migration to hosted-engine. Most of it is relevant
to any migration, if engine-backup works for you. Otherwise it's even simpler -
just copy files and hope that postgresql will manage to work with the db.
[1] http://www.ovirt.org/Migrate_to_Hosted_Engine
Good luck and best regards,
--
Didi