[ClusterLabs] Failover to spare node

[Andrei Borzenkov]

Let's say I have a pool of nodes and multiple services, somehow 
distributed across them. I would like to keep one node as "spare", 
without services by default, and if any of "worker" nodes fail, services 
that were running there should be relocated to spare together.

This ensures each service keeps the same resources available and does 
not compete with services on other nodes.

It obviously can be achieved with explicit location constraints on each 
service for "primary" and "secondary" node; but is there some generic 
trick that avoids configuring each and every service?