[ovirt-users] global vs local maintenance with single host

[Gianluca Cecchi]

On Sun, Sep 4, 2016 at 10:54 AM, Yedidyah Bar David <didi at redhat.com> wrote:

> On Sat, Sep 3, 2016 at 1:18 PM, Gianluca Cecchi
> <gianluca.cecchi at gmail.com> wrote:
> > Hello,
> > how do the two modes apply in case of single host?
> > During an upgrade phase, after having upgraded the self hosted engine and
> > leaving global maintenance and having checked all is ok, what is the
> correct
> > mode then to put host if I want finally to update it too?
>
> The docs say to put hosts to maintenance from the engine before upgrading
> them.
>
> This is (also) so that VMs on them are migrated away to other hosts.
>
> With a single host, you have no other hosts to migrate VMs to.
>
> So you should do something like this:
>
> 1. Set global maintenance (because you are going to take down the
> engine and its vm)
> 2. Shutdown all other VMs
> 3. Shutdown engine vm from itself
> At this point, you should be able to simply stop HA services. But it
> might be cleaner to first set local maintenance. Not sure but perhaps
> this might be required for vdsm. So:
> 4. Set local maintenance
> 5. Stop HA services. If setting local maintenance didn't work, perhaps
> better stop also vdsm services. This stop should obviously happen
> automatically by yum/rpm, but perhaps better do this manually to see
> that it worked.
> 6. yum (or dnf) update stuff.
> 7. Start HA services
> 8. Check status. I think you'll see that both local and global maint
> are still set.
> 9. Set maintenance to none
> 10. Check status again - I think that after some time HA will decide
> to start engine vm and should succeed.
> 11. Start all other VMs.
>
> Didn't try this myself.
>
> Best,
> --
> Didi
>

Hello Didi,
I would like to leverage the update I have to do on 2 small different lab
environments to crosscheck the steps suggested.
They are both single host environments with self hosted engine.
One is 4.0.2 and the other is 4.0.3. Both on CentoS 7.2
I plan to migrate to the just released 4.0.4

One note: in both environments the storage is NFS and is provided by the
host itself, so a corner case (for all hosted_storage domain, main data
domain and iso storage domain).
I customized the init scripts, basically for start phase of the server and
to keep in count of the NFS service, but probably something has to be done
for stop too?

1) In /usr/lib/systemd/system/ovirt-ha-broker.service

added in section [Unit]

After=nfs-server.service

The file is overwritten at update so one has to keep in mind this

2) also in vdsmd.service changed
from:
After=multipathd.service libvirtd.service iscsid.service rpcbind.service \
      supervdsmd.service sanlock.service vdsm-network.service

to:
After=multipathd.service libvirtd.service iscsid.service rpcbind.service \
      supervdsmd.service sanlock.service vdsm-network.service \
      nfs-server.service

Do you think any order setup I have to put in place related to NFS service
and oVirt services stop?
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