[ovirt-users] Affinity

[Koen Vanoppen]

Ok, thanks. Can you give me some details/example of a filter for the ovirt
schedular?

Kind regards and thank you,

Koen

2015-01-05 10:44 GMT+01:00 Doron Fediuck <dfediuck at redhat.com>:

>
> On 05/01/15 11:26, Koen Vanoppen wrote:
>
>  Thanks for your reply. But I maybe explained it badly... All the 4
> hypervisors are in the same Datacenter on oVirt. But they are physically in
> a different datacenter.
>  That is why I want to force them to run on a different hypervisor. IF 1
> physical datacenter would go down (electricity power failure or whatever)
> At least one VM will continue to run.
>
> 2015-01-05 10:21 GMT+01:00 Doron Fediuck <dfediuck at redhat.com>:
>
>>
>> On 05/01/15 10:54, Koen Vanoppen wrote:
>>
>>      Hi All,
>>
>>  First of all, let me say a Happy New Year with all the best wishes!!
>>
>>  Now, let's get down to business :-).
>>
>>  I would lik eto implement the Affinity option in our datacenter.
>>  I already activated it, put the 2 vms in it and set in on negative so
>> they won't run together on the same hypervisor. Now, the question...
>>  Is there a way I can force the VM's so they will run on a hypervisor
>> that is not in the same datacenter? We have this;
>>
>>  Hyp1 -> Datacenter1
>>  Hyp2 -> Datacenter2
>> Hyp3 -> Datacenter1
>> Hyp4 -> Datacenter2
>>
>>  For the moment they run on a different Hypervisor, but they are in the
>> same Datacenter. I can manually now move them to the other one, but I would
>> like this that oVirt manages this...
>>  Is this possible...?
>>
>>  Kind regards,
>>
>> Koen
>>
>>
>>   Hi Koen.
>>
>> VMs cannot move between data centers while still running.
>> Just to provide some basic concepts in terms of hierarchy, we have:
>>
>> Data-Center1
>> |
>> |\ Cluster A
>> | |
>> | |\ Host (a)
>> | |\ Host (b)
>> |
>> |\ Cluster B
>> | |
>> | |\ Host (c)
>> | |\ Host (d)
>> | |\ Host (e)
>>
>> Data-Center2
>> |
>> |\ Cluster A
>> | |
>> | |\ Host (f)
>> |
>> |\ Cluster B
>> | |
>> | |\ Host (g)
>> | |\ Host (h)
>> | |\ Host (i)
>>
>> As you can see, a host may be a part of a single cluster and a VM
>> will run on one of the hosts. Live migration can be done between
>> hosts of the same cluster. The only way to move VM between clusters
>> and DCs are when the VM is down, in a manual way.
>>
>> So Affinity works in the cluster level, and the rules are valid for a
>> specific cluster who currently owns the VM.
>> In your case if Hyp1 and Hyp3 belong to the same cluster, the affinity
>> rules will apply every time you start or migrate a VM. However, there's
>> no rule which is valid for Datacenter1 and Datacenter2.
>>
>> HTH,
>> Doron
>>
>
>
> Koen,
> this is clear now.
> Currently affinity applies to VMs only. For 3.6 we're planning "pin to
> hosts"
> which will allow you to pin VMs to a group of hosts, such as Datacenter1
> hosts
> in your case. Until 3.6 will be available (which will take a while), you
> can consider
> writing a filter module for the ovirt scheduler. Let me know if you need
> more
> details.
>
> Doron
>
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