[ovirt-users] Ovirt resilience policy / HA

Omer Frenkel ofrenkel at redhat.com
Wed Mar 18 10:18:43 UTC 2015



----- Original Message -----
> From: "Guillaume Penin" <guillaume at onlineacid.com>
> To: users at ovirt.org
> Sent: Monday, March 16, 2015 10:34:54 PM
> Subject: [ovirt-users] Ovirt resilience policy / HA
> 
> Hi all,
> 
> I'm building a test ovirt (3.5.1) infrastructure, based on 3 ovirt nodes
> and 1 ovirt engine.
> 
> Everything runs (almost) fine, but i don't exactly understand the
> interaction between resilience policy (Cluster) and HA (VM).
> 
> => What I understand, in case of host failure :
> 
> - Setting resilience policy to :
> 
>      - Migrate Virtual Machines => All VMs (HA and non HA) will be
> started on another host.
>      - Migrate only Highly Available Virtual Machines => HA VMs only will
> be started on another host.
>      - Do Not Migrate Virtual Machines => HA and non HA VMs won't be
> started on another host.
> 
> => In practice :
> 
>      - No matter what parameter i use in resilience policy, HA VMs only
> will be started on another host in case of a host failure.
> 
> Is this the expected behaviour ? Am I misunderstanding the way it works
> ?
>

there are 2 types of host failure:
1 - power/network/vdsm service.. - these leads to a state where engine and host cannot communicate, host will move to 'non-responsive' and will be fenced (power mgmt action)
in this case, only HA vms will be restarted, once the engine is sure it is safe.

2 - software issues like storage connectivity - in this case, engine can communicate with the host, and decide it is not fulfilling the cluster/dc requirements
the host will move to 'not operational' then the engine will live-migrate (not restart) vms according to your choice of resilience policy 

so what did you do when you tested 'host failure'?
according to your question i assume number 1, and this is what you got

let me know if it helps
Omer.

> Kind regards,
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