Runtime Briefing — Kubernetes 1.20 Release
Kubernetes 1.20 shipped on 8 December 2020 with CSI volume snapshots graduating to GA, built-in kubectl debug tooling, and a formal Docker shim deprecation plan, requiring platform teams to validate workloads and container runtimes ahead of upgrades.
Executive briefing: Kubernetes v1.20 became generally available on , delivering maturity milestones for persistent storage and node operations while signalling the deprecation of the dockershim container runtime.
Key changes to evaluate
- Persistent volumes. CSI volume snapshots reached GA, enabling fully supported backup and restore workflows that many regulated teams require.
- Troubleshooting tools. The new
kubectl debugcommand promotes ephemeral container debugging, reducing the need for privileged SSH access during incidents. - Runtime roadmap. The dockershim removal notice requires clusters to standardise on CRI-compliant runtimes such as containerd or CRI-O before future releases.
Migration guidance
- Test backup automation, stateful workloads, and snapshot restore procedures using the GA CSI APIs before rolling the release to production clusters.
- Update platform runbooks and RBAC policies to reflect the new
kubectl debugcapabilities and ensure only authorised responders can attach ephemeral containers. - Inventory clusters that still rely on Docker Engine, plan migrations to containerd/CRI-O, and document runtime changes for security and compliance assessments.
Follow-up: Kubernetes 1.20 support ended in December 2021; modern clusters are expected to run releases such as 1.28+ to benefit from CSI migration completion, Dockershim removal, and Pod Security admission.
Sources
- Kubernetes v1.20: The Raddest Release — Kubernetes.io; Official release blog outlining the GA of CSI volume snapshots, kubectl debug, and dockershim deprecation plans.
- Kubernetes 1.20 Release Notes — Kubernetes Documentation; Detailed change log covering feature graduations, removals, and known issues for the 1.20 release train.