kyverno/samples/DisallowBindMounts.md

Disallow use of bind mounts (hostPath volumes)

The volume of type hostPath allows pods to use host bind mounts (i.e. directories and volumes mounted to a host path) in containers. Using host resources can be used to access shared data or escalate privileges. Also, this couples pods to a specific host and data persisted in the hostPath volume is coupled to the life of the node leading to potential pod scheduling failures. It is highly recommended that applications are designed to be decoupled from the underlying infrastructure (in this case, nodes).

Policy YAML

disallow_bind_mounts.yaml

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: disallow-bind-mounts
spec:
  validationFailureAction: audit
  rules:
  - name: validate-hostPath
    match:
      resources:
        kinds:
        - Pod
    validate:
      message: "Host path volumes are not allowed"
      pattern:
        spec:
          =(volumes):
          - X(hostPath): "null"