Re: [ovirt-users] Affinity

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(a)redhat.com&gt;: > > 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