12.2. Placement Strategy
After you have configured the capacities your nodes provide and the capacities your resources require, you need to set the placement-strategy in the global cluster options, otherwise the capacity configurations have no effect.
Four values are available for the placement-strategy:
default
Utilization values are not taken into account at all. Resources are allocated according to allocation scores. If scores are equal, resources are evenly distributed across nodes.
utilization
Utilization values are taken into account only when deciding whether a node is considered eligible (i.e. whether it has sufficient free capacity to satisfy the resource’s requirements). Load-balancing is still done based on the number of resources allocated to a node.
balanced
Utilization values are taken into account when deciding whether a node is eligible to serve a resource and when load-balancing, so an attempt is made to spread the resources in a way that optimizes resource performance.
minimal
Utilization values are taken into account only when deciding whether a node is eligible to serve a resource. For load-balancing, an attempt is made to concentrate the resources on as few nodes as possible, thereby enabling possible power savings on the remaining nodes.
Set placement-strategy with crm_attribute:
# crm_attribute --name placement-strategy --update balanced
Now Pacemaker will ensure the load from your resources will be distributed evenly throughout the cluster, without the need for convoluted sets of colocation constraints.
