What’s New in Kubernetes v1.20? 42 Enhancements Explained

On December 8, Kubernetes v1.20 was officially released, marking the third and final release of 2020.

This version includes 42 enhancements: 11 approaching stability, 15 in Beta, and 16 in Alpha.

The release cycle returned to a normal 11‑week cadence, making it one of the most feature‑dense releases, with more Alpha features than stable ones, indicating ample exploration space in the cloud‑native ecosystem.

Major Themes

The new release focuses on the following themes:

1. Storage Volume Snapshots Stabilize

Standard methods to trigger volume snapshots are now provided, allowing portable snapshot operations across Kubernetes clusters or any supported storage provider.

The snapshot primitives serve as building blocks for enterprise‑grade storage management, including application and cluster backup solutions.

Support requires vendors to bundle the Snapshot controller, Snapshot CRD, and validation webhook, and CSI drivers must be deployed.

2. Kubectl Debug Enters Beta

The former kubectl alpha debug feature is now kubectl debug in Beta, offering built‑in debugging workflows.

Supported troubleshooting scenarios include:

Creating a Pod copy with a different container image to resolve startup crashes.

Adding a new container with debugging tools to a Pod copy or temporary container (the latter is an Alpha feature) to debug Distroless containers.

Launching a container in the host namespace with host filesystem access to debug nodes.

As a built‑in command, kubectl debug takes precedence over any plugin named “debug”, so affected plugins must be renamed. The kubectl alpha debug command is deprecated and will be removed in future releases.

3. API Priority and Fairness (Beta)

The API Priority and Fairness (APF) feature introduced in v1.18 is now enabled by default, allowing the kube‑apiserver to classify incoming requests by priority.

4. IPv4/IPv6 Dual‑Stack Alpha Updates

The dual‑stack implementation now permits assigning both IPv4 and IPv6 service cluster IPs to a single service and toggling between single‑stack and dual‑stack modes.

5. GA: PID Limits

PID limits help prevent host instability by ensuring Pods do not exhaust process IDs, with mechanisms like SupportNodePidsLimit and SupportPodPidsLimit moving the feature to GA.

6. Alpha: Graceful Node Shutdown

The GracefulNodeShutdown feature, now in Alpha, informs the kubelet of node shutdown, allowing Pods to terminate gracefully during system shutdown.

Important Updates

1. Dockershim Deprecation

Dockershim, the Docker container runtime interface, is deprecated in v1.20 and will be removed in future releases, though Docker images remain OCI‑compliant.

2. Exec Probe Timeout Fix

A long‑standing bug where exec probes ignored timeoutSeconds has been fixed; the default timeout is now 1 second, and a new feature gate ExecProbeTimeout allows reverting to the previous behavior.

Other Updates

Features that have reached stability include RuntimeClass, default values for built‑in API types, Pod‑Startup Liveness‑Probe delay, CRI‑ContainerD support on Windows, SCTP Service support, and AppProtocol addition to Service and Endpoint.

Notable functional updates: CronJobs (#19) for scheduled tasks such as backups and report generation.

For more details, refer to the official Kubernetes blog and changelog links.