On Sun, Mar 12, 2017 at 7:57 AM, Yedidyah Bar David <didi@redhat.com> wrote:

On Fri, Mar 10, 2017 at 3:43 PM, Devin A. Bougie
<devin.bougie@cornell.edu> wrote:
> Hi, All. We have an ovirt 4.1 cluster setup using multiple paths to a single iSCSI LUN for the data storage domain. I would now like to migrate to a hosted engine.
>
> I setup the new engine VM, shutdown and backed-up the old VM, and restored to the new VM using engine-backup. After updating DNS to change our engine's FQDN to point to the hosted engine, everything seems to work properly. However, when rebooting the entire cluster, the engine VM doesn't come up automatically.

I am aware that the above flow is technically possible - nothing stops
you from doing it - but it's not the standard/supported/expected way
to deploy a hosted-engine. You must use 'hosted-engine --deploy' for
that.
Nice try, though :-) Will be an interesting exercise to try and
convert this to a fully-functioning hosted-engine, but I'd personally
not try that on a production system.

On the hosted-engine storage domain we have also the lockspace, metadata and configuration volumes.

They are created at setup time by ovirt-hosted-engine-setup

>
> Is there anything that now needs to be done to tell the cluster that it's now using a hosted engine?

Yes, but it's currently not possible to do this after the fact.

>
> I started with a standard engine setup, as I didn't see a way to specify multiple paths to a single iSCSI LUN when using "hosted-engine --deploy."

I think it's indeed not fully-supported yet [1], but can be done
manually [2][3].

Simone - are there updates for this? Perhaps we should add this to the
hosted-engine howto page.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1193961
[2] http://lists.ovirt.org/pipermail/users/2015-March/032034.html
[3] https://bugzilla.redhat.com/show_bug.cgi?id=1193961#c2

Here we have two distinct things:

- use multiple iSCSI initiators on the host; the best way to achieve this is configuring an iSCSI bond from the engine once it's running. See 'Configuring iSCSI Multipathing' section on http://www.ovirt.org/documentation/admin-guide/chap-Storage/

- get multipath connecting to multiple targets on the same SAN: this is currently not supported by hosted-engine-setup and ovirt-ha-agent

>
> Any tips would be greatly appreciated.
>
> Many thanks,
> Devin
> _______________________________________________
> Users mailing list
> Users@ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users

--
Didi