[ClusterLabs] Need information for N+M clustering using Pacemaker

[Ken Gaillot]

On 04/16/2015 08:52 AM, Sayed Mujtaba wrote:
> I am trying to form M+N clustering along with Load balancer using Pacemaker
> and not getting the enough information .Can someone please guide me about
> this set up .
> Cluster from scratch document doesn't cover this topic.

Hi,

It should be as simple as assigning your resources a higher location
preference on your primary nodes than your failover nodes.

However the only reason I can think of to do N+M is if the failover
nodes are less powerful (CPU/RAM/whatever), and that's why you don't
want to use them normally. If your nodes are roughly equivalent, you can
just let Pacemaker spread out the resources on whichever nodes are
available. You don't have to designate particular ones as failover.

Meaning of location constraint scores:

* -INFINITY: never run this resource on this node

* negative: i'd prefer not to run this resource on this node, unless
other factors are more important (for example, no other node is available)

* positive: i'd prefer to run this resource on this node, but it's OK
not to if other factors are more important

* INFINITY: always run this resource on this node if it's available