[ovirt-users] oVirt 3.6 on CentOS 6.7 based HyperConverged DC : Upgradable?

[Yedidyah Bar David]

On Wed, Mar 29, 2017 at 4:35 PM, Nicolas Ecarnot <nicolas at ecarnot.net> wrote:
> [Please ignore the previous msg]
>
> Hello,
>
> One of our DC is a very small one, though quite critical.
> It's almost hyper converged : hosts are compute+storage, but the engine is
> standalone.

And you intend to keep it that way? You didn't mention below.

>
> It's made of :
>
> Hardware :
> - one physical engine : CentOS 6.7
> - 3 physical hosts : CentOS 7.2
>
> Software :
> - oVirt 3.6.5
> - glusterFS 3.7.16 in replica-3, sharded.
>
> The goal is to upgrade all this to oVirt 4.1.1, and also upgrade the OSes.
> (oV 4.x only available on cOS 7.x)
>
> At present, only 3 VMs here are critical, and I have backups for them.
> Though, I'm quite nervous with the path I have to follow and the hazards.
> Especially about the gluster parts.
>
> At first glance, I would go this way (feel free to comment) :
> - upgrade the OS of the engine : 6.7 -> 7.3

How? This isn't supported, in principle, although it might work.
The "official" way is using engine-backup to backup and restore it.
See also:
https://bugzilla.redhat.com/show_bug.cgi?id=1332463

> - upgrade the OS of the hosts  : 7.2 -> 7.3
> - upgrade and manage the upgrade of gluster, check the volumes...
> - upgrade oVirt (engine then hosts)
>
> But when upgrading the OSes, I guess it will also upgrade the gluster layer.

I know nothing about gluster, so won't comment.

>
> During this upgrade, I have no constraint to keep everything running, total
> shutdown is acceptable.

So you can also do a full backup and restore. Create an NFS export domain
somewhere, export all your VMs there, recreate everything from scratch,
import the VMs. Will take much longer, but then you don't need to risk/
test/prepare for problems in upgrading gluster.

>
> Is the above procedure seems OK, or may am I missing some essential points?
>
> Thank you.
>
> --
> Nicolas ECARNOT
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-- 
Didi