[ClusterLabs] Moving Related Servers

[Ken Gaillot]

On 04/18/2016 02:34 AM, ‪H Yavari‬ ‪ wrote:
> Hi,
> 
> I have 4 CentOS servers (App1,App2.App3 and App4). I created a cluster
> for App1 and App2 with a IP float and it works well.
> In our infrastructure App1 works only with App3 and App2 only works with
> App4. I mean we have 2 server sets (App1 and App3) , (App2 and App4).
> So I want when server app1 is down and app2 will Online node, App3 will
> offline too and App4 will Online and vice versa, I mean when App3 is
> down and App4 will Online, App1 will offline too.
> 
> 
> How can I do with pacemaker ? we have our self service on servers so how
> can I user Pacemaker for monitoring these services?
> 
> Thanks for reply.
> 
> Regards.
> H.Yavari

I'm not sure I understand your requirements.

There's no way to tell one node to leave the cluster when another node
is down, and it would be a bad idea if you could: the nodes could never
start up, because each would wait to see the other before starting; and
in your cluster, two nodes shutting down would make the cluster lose
quorum, so the other nodes would refuse to run any resources.

However, it is usually possible to use constraints to enforce any
desired behavior. So even those the node might not leave the cluster,
you could make the cluster not place any resources on that node.

Can you give more information about your resources and what nodes they
are allowed to run on? What makes App1 and App3 dependent on each other?