kyverno/samples/MutateSafeToEvict.md

Mutate pods with emptyDir and hostPath with safe-to-evict

The Kubernetes cluster autoscaler does not evict pods that use hostPath or emptyDir volumes. To allow eviction of these pods, the following annotation must be added to the pods:

cluster-autoscaler.kubernetes.io/safe-to-evict: true

This policy matches and mutates pods with emptyDir and hostPath volumes, to add the safe-to-evict annotation if it is not specified.

Policy YAML

add_safe_to_evict_annotation.yaml

apiVersion: "kyverno.io/v1alpha1"
kind: "ClusterPolicy"
metadata: 
  name: "annotate-emptydir-hostpath"
spec: 
  rules: 
  - name: "empty-dir-add-safe-to-evict"
    match: 
      resources: 
        kinds: 
        - "Pod"
    mutate: 
      overlay:
        metadata:
          annotations:
            +(cluster-autoscaler.kubernetes.io/safe-to-evict): true
        spec:          
          volumes: 
          - (emptyDir): {}
  - name: "host-path-add-safe-to-evict"
    match: 
      resources: 
        kinds: 
        - "Pod"
    mutate: 
      overlay:
        metadata:
          annotations:
            +(cluster-autoscaler.kubernetes.io/safe-to-evict): true
        spec:          
          volumes: 
          - (hostPath):
              path: "*"