7.4. Pod placement rules

Kubernetes is responsible for pod placement based on declarative placement rules. The Red Hat OpenShift Data Foundation base service placement rules for Internal cluster can be summarized as follows:

This leads to the requirement that there be at least three nodes, and that nodes be in three distinct rack or zone failure domains in the case of pre-existing topology labels.

For additional device sets, there must be a storage device, and sufficient resources for the pod consuming it, in each of the three failure domains. Manual placement rules can be used to override default placement rules, but generally this approach is only suitable for bare metal deployments.