gke/ERR/2021_009
Version skew between cluster and node pool
Product: Google Kubernetes Engine
Rule class: ERR - Something that is very likely to be wrong
Description
Difference between cluster version and node pools version should be no more than 2 (K8s <v1.28) or 3 (K8s v1.28+) minor versions.
For example: Cluster 1.19.12-gke.2101, Node Pool: 1.14.10-gke.36 Such a big difference is not supported.
In this situation the cluster might be stuck in auto-repair.
Remediation
Upgrade the problematic node pool or recreate it with a later version.