[Pacemaker] Manging Virtual Machine's resource

[Andrew Beekhof]

On May 19, 2008, at 9:07 AM, Nitin wrote:

> On Mon, 2008-05-19 at 08:34 +0200, Andrew Beekhof wrote:
>> On May 19, 2008, at 7:14 AM, Nitin wrote:
>>
>>> On Fri, 2008-05-16 at 15:08 +0200, Andrew Beekhof wrote:
>>>> On May 16, 2008, at 3:04 PM, Nitin wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> I would like to make my virtual machines (DomUs) resources to
>>>>> participate in the HA cluster. Dom0 (Physical Host) may or may not
>>>>> have
>>>>> resources.
>>>>>
>>>>> To do this I would like to treat DomUs as *resource* in the
>>>>> cluster as
>>>>> opposed to treating them as *nodes*. I am planning to write OCF
>>>>> resource
>>>>> agents for virtual machines. But I am not very sure about how to
>>>>> make a
>>>>> resource's resource to participate in the cluster.
>>>>>
>>>>> Is there any configuration in existing structure to achieve this??
>>>>> If no
>>>>> then please tell me how to go about creating a "container"
>>>>> resource in
>>>>> CRM.
>>>>
>>>> Why not just use the Xen agent if you don't want them to be cluster
>>>> nodes?
>>>> Or do you mean that you want them to both be resources and to run
>>>> other resources too?
>>>
>>> Yes. Please advise me how to go about it.
>>> Thanks a lot for reply.
>>
>> We don't have a clean way to do that yet
>>
>> Possible options:
>> a) start the services at VM boot (you don't get monitoring)
>> b) start the services at VM boot and modify the Xen agent to monitor
>> the services inside the VM (ugly)
>> c) add a proxy resource to start/stop/monitor the services inside the
>> VM (complex)
> Did you mean writing a OCF RA which will take care of start/stop/ 
> monitor inside VMs ??

right

>
> Can we configure how CRM will handle resource failures in this case??

as far as the crm knows, its just another resource

>
> For example if res1 at VM1 fails
> 	     retry on same VM
> 		success --> OK
> 		failure --> start res1 (with group dependencies/collocation  
> preferences) at VM2 on same node

no - the cluster doesn't know that VM1 or VM2 is a cluster node.
so (for option 'c') the cluster will never allocate the resource to a  
specific virtual machine - thats up to you.

>
> 			(success -- OK)
> 			failure --> start res1 as direct resource to node
> 			..........
> 			..........
> 			
> 			finally use Passive node's VM
> 			
> 				
> 	
>> d) implement a generic version of c)
> I guess it would be required otherwise we have to write a proxy  
> resource
> (c) for each resource type. Right??

depends on what your needs are

>
>
>> e) have the VM join the cluster (makes stonith and quorum  
>> "interesting")
>> f) wait for us to implement clusters-of-clusters which also solves
>> this scenario "for free"
>> g) something else i've not thought of
>>
>> _______________________________________________
>> Pacemaker mailing list
>> Pacemaker at clusterlabs.org
>> http://list.clusterlabs.org/mailman/listinfo/pacemaker
>
>
> _______________________________________________
> Pacemaker mailing list
> Pacemaker at clusterlabs.org
> http://list.clusterlabs.org/mailman/listinfo/pacemaker