I understand your sense of panic, I accidentally destroyed my RHEV manager a few months ago, and it was quite a bad time.  It sounds like you have some good suggestions on how to recover, I just wanted to share some experience with you.

Your hypervisors will happily continue running your vm's, as long as nothing interrupts them.  If a guest shuts down or hangs, you'll have no way to start it back up or reboot it.  likewise, if a hypervisor crashes, you wont be able to start it's guests back up.

Your storage domains should be importable into 4.2 from 4.1.  One of the clusters I'd broken was fixed that way.  I did have to log into each guest and shut it down before I could safely bring the storage domain into my new manager though.  I was going from a broken 3.6 manager to a new 4.1 manager in that case.  Not sure if its different from 4.1 to 4.2.

The procedure went something like this, from my memory: Build a new 4.1 manager. Shut down vm's on your rhev/oVirt hypervisors.  Reinstall one of the hypervisors, and join it to the new manager.  Attach your storage domains using the Import Domain button, not the New domain button.  Domain should come in, and have all of your vms listed. Reinstall the rest of the hypervisors, and join them to the new manager. I believe I had to activate, or import each VM as well.  It's been several months since I did all that.

I'm not sure if you're working with upstream oVirt, or RHV, i'm on RHV.  My 4.1 repos are certainly still available from Red Hat.  Not sure about the status of oVirt repos.



On Mon, Oct 29, 2018 at 10:27 AM David Johnson <djohnson@maxistechnology.com> wrote:
Thank you for your generous help.

4.1 wouldn't install because a number of dependencies were pointing to dead links. It felt like over half, although I'm sure it was a more limited subset.

I will give these suggestions a try


On Mon, Oct 29, 2018, 4:50 AM Yedidyah Bar David <didi@redhat.com> wrote:
On Mon, Oct 29, 2018 at 10:00 AM Simone Tiraboschi <stirabos@redhat.com> wrote:
>
> Hi,
> AFAIK https://resources.ovirt.org/pub/ovirt-4.1/ is still there, maybe you could find some issues with other repos.
>
> If you want to take a shortcut, https://resources.ovirt.org/pub/ovirt-4.1/rpm/el7/noarch/ovirt-engine-appliance-4.1-20180124.1.el7.centos.noarch.rpm contains latest 4.1 based engine appliance.
> You can extract the OVA file from there and use it to boot a temporary VM with virt-install and then upgrade the engine there to 4.2 in order to take a new 4.2 based backup that your can restore where you prefer with up to date rpms.
>
>
> On Mon, Oct 29, 2018 at 8:49 AM <djohnson@maxistechnology.com> wrote:
>>
>> I'm looking for a hand in recovering my ovirt cluster from a hardware failure. The hard drive on my cluster controller failed, and I would like to recover from backup.
>>
>> The problem is, the cluster was 4.1, which is less than a year old, but was nevertheless removed from the active repositories back in May. 4.2 will not recover from 4.1 backups.

If you are brave, you can also "cheat" - patch engine-backup to allow
recovering 4.1. That's a trivial patch, and the main problem with it
is that no-one tested it, and I do expect it might introduce subtle
issues. But considering the alternatives, it might be a reasonable
approach. If you do, try restoring first on an _isolated_ VM somewhere,
try to see how the engine behaves after restore (it will not work
very well, because it will not manage to access its hosts - if you
indeed isolated it well enough), and if it looks ok, try for real.

See also e.g.:

https://lists.ovirt.org/pipermail/users/2017-March/080346.html

https://bugzilla.redhat.com/show_bug.cgi?id=1425788

That said, not sure why 4.1 does not work for you. I think it should
still work, although I didn't try by myself recently.

Good luck and best regards,

>>
>> The storage domains are all intact (I think), and the hosts are still running (unmanaged). I've tried to manually restore the engine from backups, but either the upgrade is reinitializing or I am missing something.
>>
>> Any ideas?
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--
Didi
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