[Pacemaker] Resource colocation

[Diego Julian Remolina]

> Now that's where the things get interesting, I want to relocate the IP
> 
> address on another node _if_ nginx fails on the node on which the IP
> runs.

Are you already addressing network connectivity with pingd or something else? In your model it would be possible to move the IP address to a node with nginx running but no network connectivity.

Do you need the services running at all times on all nodes with the IP changing from one to another for some other reason? Please explain this reason. If you only need to run apache and nginx on a node connected to the network and capable of serving, then the model will be different.

You have to be careful with colocation in the sense that it sometimes will prevent a resource from running in both nodes.

You can see a colocation example for my fileserver with drbd posted in a previous message to the list called: "Master/Slave resource cannot start" I was missing the cloned resource and had a bad colocation rule. After that was pointed out to me, I fixed my configuration which is posted in a reply later down the road. That configuration is working well for me.

HTH,

Diego