[ovirt-users] Affinity

[Artyom Lukianov]

If you want that each vm will run on different host, you can:
1) just not pinned it to specific host(placement and migration options under vm properties)?
2) create two clusters, each cluster will have hosts from different physical datacenters, and for each cluster administrate different set of vms.
3) And in the end we have possibility to use external scheduler, so you can write your own python script, and use it as filter, weight or balance module for ovirt scheduler:
   http://www.ovirt.org/Features/oVirt_External_Scheduling_Proxy
   http://www.ovirt.org/External_Scheduler_Samples 

   You need to install package ovirt-scheduler-proxy and also enable it via engine-config -s ExternalSchedulerEnabled=True.
   Also additional info you can find under cd /usr/share/doc/ovirt-scheduler-proxy*

I hope it will help you.
Thanks

----- Original Message -----
From: "Koen Vanoppen" <vanoppen.koen at gmail.com>
To: "Doron Fediuck" <dfediuck at redhat.com>, users at ovirt.org
Sent: Monday, January 5, 2015 11:26:26 AM
Subject: Re: [ovirt-users] Affinity

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 


_______________________________________________
Users mailing list
Users at ovirt.org
http://lists.ovirt.org/mailman/listinfo/users