[ovirt-users] 3.5.6 to 4.0

[Yedidyah Bar David]

On Thu, Jul 14, 2016 at 10:38 AM, Demeter Tibor <tdemeter at itsmart.hu> wrote:
>
> Dear members!
>
> We have an ovirt cluster that based on el6 and 3.5.6
> It is contain three nodes, but the first node is an all-in-one installation.
> I would like to upgrade the whole system to 4.0. Also I would like to switch
> to hosted engine modell.

Sounds like a combination of:

[1] http://www.ovirt.org/develop/developer-guide/engine/migrate-to-hosted-engine/
[2] https://www.ovirt.org/documentation/how-to/hosted-engine-host-OS-upgrade/
[3] https://www.ovirt.org/documentation/how-to/hosted-engine/#upgrade-hosted-engine

> Now, we bought new servers for the migration.

"For the migration", meaning you intend to eventually migrate to them?
And decommission the existing ones?

Also, I assume you want el7 on all hosts eventually.

Storage remains as-is?

How important is no downtime for the VMs?

>
> What is the good way to migrate nodes, etc?

Something like:
1. Create new storage space for the hosted-engine
2. Install el7 on one of the new hosts, NH1
3. deploy hosted-engine on NH1
Follow [1]:
- backup existing engine and stop/disable engine there
- restore backup on the engine vm (after you install engine,
but do not engine-setup)
- engine-setup
- When 'hosted-engine --deploy' will try to add the host to
the engine, it might fail, because it will add it to Default
cluster, which has el6 hosts. Check [2] about this - create
new cluster and add there.
- All of the above in 3.5.
4. Perhaps add the other new hosts, perhaps as hosted-engine
hosts - if you want HA for the engine vm
5. Migrate all VMs to the new cluster.
6. Delete old hosts
7. Upgrade to 3.6 - check [2]
8. Upgrade to 4.0 - should be normal procedure [3]

I recommend testing this on test systems prior to prod.
You can use nested kvm for this.

Best,
-- 
Didi