Cluster Autoscaler is not scaling down nodes in OCP 4

Issue

• How to check why the Cluster Autoscaler is not scaling down nodes in OpenShift 4?

• There are messages in the cluster-autoscaler pod preventing nodes to be removed by the Cluster Autoscaler:

  Skipping [node_name] - node group min size reached
  [...]
  Fast evaluation: node [node_name] cannot be removed: pod with local storage present: [pod_name]
  [...]
  Fast evaluation: node [node_name] cannot be removed: openshift-marketplace/[pod_name] is not replicated
  [...]
  Fast evaluation: node [node_name] cannot be removed: pod annotated as not safe to evict present: [pod_name]