[Pacemaker] pacemaker resource constraints

[Dejan Muhamedagic]

Hi,

On Mon, Mar 22, 2010 at 09:29:50AM -0700, Alan Jones wrote:
> Friends,
> I have what should be a simple goal.  Two resources to run on two nodes.
> I'd like to configure them to run on separate nodes when available, ie.
> active-active,
> and provide for them to run together on either node when one fails, ie.
> failover.
> Up until this point I have assumed that this would be a base use case for
> Pacemaker, however, it seems from the discussion on:
> http://wiki.lustre.org/index.php/Using_Pacemaker_with_Lustre
> ... that it is not (see below).  Any ideas?

Why not just two location constraints (aka node preferences):

location l1 rsc1 100: node1
location l2 rsc2 100: node2

Thanks,

Dejan

> Alan
> 
> *Note:* Use care when setting up your point system. You can use the
> point system if your cluster has at least three nodes or if the resource
> can acquire points from other constraints. However, in a system with
> only two nodes and no way to acquire points, the constraint in the
> example above will result in an inability to migrate a resource from a
> failed node.
> 
> The example they refer to is similar to yours:
> 
> # crm configure colocation colresOST1resOST2 -100: resOST1 resOST2

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