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Pod Security Policies

Mostly notes from watching TGI Kubernetes 078: Pod Security Policies
  • Pod Security Policies (PSP) are mechanism to prevent security aspects and capabilities of containers.
  • It is implemented by as an optional, but recommended, admission controller
  • Depending on the platform and Kubernetes distribution, PSP might need to enabled first
  • PSPs are cluster-wide resources
  • Kubernetes objects need to be granted privileges to use PSPs by RBAC
    • For example, create ClusterRole and then RoleBinding to bind it to specific namespaces
  • In my opinion, PSPs should be used in every production cluster
  • It is recommended to create multiple PSPs for different types of workloads. For example:
    • More privileged PSP for kube-system pods. Check TGIK 078 or Kube docs example for this.
    • Restricted for "normal" workloads
    • Something in between, if needed
  • You can use kubectl describe/get $OBJECT to check which PSP the pod is using from its annotations
  • In order to create a default and restrictive policy which always resolves, use ClusterRoleBinding and bind to rule to group system:authenticated
  • Security context configures security aspects for the pods
  • You can provide exceptions to PSPs on
    • workload level
      • binding the role to specific ServiceAccount
    • namespace level
    • Advices the set of PSP against your workload

References

Last modified 3yr ago