[ovirt-users] VDSM Shutdown Scenario

[Barak Azulay]

----- Original Message -----
> From: "Neil" <nwilson123 at gmail.com>
> To: users at ovirt.org
> Sent: Wednesday, April 16, 2014 12:29:24 PM
> Subject: [ovirt-users] VDSM Shutdown Scenario
> 
> Hi guys,
> 
> I'm trying to setup the simplest yet safest way of protecting my
> guests during an unexpected power outage.

One general question - do all hosts connected to the same UPS ? or each host has a different UPS ?
If it's a single UPS than it is easy to detect general outage, in case it's multiple UPSs it a bit harder.

> 
> If I'm running ovirt with 3 hosts, and the ovirt-engine machine as
> well as the hosts have SNMP UPS monitoring software installed and
> configured to shutdown if the UPS starts running out of power, what
> would happen to the guests when the hosts commence the shutdown
> sequence caused by the UPS software? 

I assume it's a standard shutdown command,
So the VMs should survive that .. like any other linux process on shutdown.
If you want to be on the safe side you can either shutdown or suspend all the VMs (using RestAPI to the engine).
If you want to suspend you must take under consideration the fact that suspend takes much more time and you should be able to estimate whether the UPS has enough power till this process is done.


> The ovirt-engine would also be
> configured to shutdown during the outage.
> 
> Would the guests try to migrate to another host (despite all of the
> hosts commencing the shutdown)? 

The VMs would try to migrate automatically when host becomes non-operational. which is not the case here.
Unless your storage or network are out as well.

> Would the guests be paused?
> 

The guests would pause in 2 cases:
- you send them pause command
- they receive EIO from their storage.

> What is the recommended practice to safely protect the VM's ?

After concluding this is a general outage (depends on your env) 
I would shutdown all VMs enough time before the power runs out from the UPS

> 
> Thank you!
> 
> Regards.
> 
> Neil Wilson.
> _______________________________________________
> Users mailing list
> Users at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
> 
> 
>