[ovirt-users] Engine Backup/Restore Question

[Yedidyah Bar David]

On Fri, Sep 15, 2017 at 3:04 PM, Alan Griffiths <apgriffiths79 at gmail.com> wrote:
> Hi,
>
> Currently testing my recovery plan for HE failure.
>
> I run a hosted engine, but in the event of some failure of the engine VM i
> want to be able to quickly restore the engine to a standalone host running
> independent of Ovirt (in this case a VM running on ESXi).
>
> On a dry run I restore the backup onto the ESXi VM and run engine-setup. At
> this point it fails with an error that I am not in Global Maintenance mode.

How do you backup, and how do you restore?

>
> If I put the cluster into maintenance mode before performing the backup then
> it works correctly. So is it necessary to do this on every backup? I can
> find nothing in the documentation detailing this as a requirement?

You might want to look at this:

https://bugzilla.redhat.com/show_bug.cgi?id=1403903

and the linked patches.

>
> Alternatively it seems I can manually update the ha_global_maintenance
> column in the vds_statistics table before running engine-setup, but not sure
> of the implications of doing this.

The way this works with engine-backup is:

We added a new option DbJustRestored, which defaults to False.

engine-backup --mode=restore sets it to True.

engine-setup checks if it's False, and if so, goes on to check
ha_global_maintenance.

So in principle, it should be enough to:

UPDATE vdc_options SET option_value='1' WHERE option_name='DbJustRestored';

However, this isn't exposed to engine-config, and is not considered an
"external/official API".

>
> ovirt-4.0.6.3

Above is for 4.1. You might want to upgrade.

Or just reset ha_global_maintenance, but I am not aware of anyone
verifying this or analyzing the implications.

Best,
-- 
Didi