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Getting Ready for Dockershim Removal in 1.24

Kubernetes 1.24, due in May 2022, removes dockershim. Check your nodes and your pipelines.

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  • Kubernetes 1.23
  • containerd 1.6
  • Kubernetes 1.24

Kubernetes 1.24 is expected in May 2022 and will no longer include dockershim. The kubelet will talk to a CRI runtime such as containerd or CRI-O directly.

Check what each node uses:

kubectl get nodes -o wide        # CONTAINER-RUNTIME column

Images are unaffected: anything built with docker build still runs. What can break:

  • Pods that mount /var/run/docker.sock to build or inspect images.
  • Monitoring or log agents that read the Docker socket or Docker log paths.
  • Scripts that run docker ps on nodes for debugging.

Replacements: use crictl ps on nodes; build images with Kaniko, BuildKit or Buildah in CI, or build outside the cluster.

On kubeadm clusters the runtime is switched per node with a drain, a runtime change and an uncordon. On EKS and other managed services the provider changes the node image, so watch their announcements. Practise on a test cluster now, not during the upgrade window.