Kubernetes 1.23: The Next Frontier

Tuesday, December 07, 2021

Authors:

We’re pleased to announce the release of Kubernetes 1.23, the last release of 2021!

This release consists of 47 enhancements: 11 enhancements have graduated to stable, 17 enhancements are moving to beta, and 19 enhancements are entering alpha. Also, 1 feature has been deprecated.

Major Themes

HorizontalPodAutoscaler v2 graduates to GA

The HorizontalPodAutscaler autoscaling/v2 stable API moved to GA in 1.23. The HorizontalPodAutoscaler autoscaling/v2beta2 API has been deprecated.

Generic Ephemeral Volume feature graduates to GA

The generic ephemeral volume feature moved to GA in 1.23. This feature allows any existing storage driver that supports dynamic provisioning to be used as an ephemeral volume with the volume’s lifecycle bound to the Pod. All StorageClass parameters for volume provisioning and all features supported with PersistentVolumeClaims are supported.

Skip Volume Ownership change graduates to GA

The feature to configure volume permission and ownership change policy for Pods moved to GA in 1.23. This allows users to skip recursive permission changes on mount and speeds up the pod start up time.

Allow CSI drivers to opt-in to volume ownership and permission change graduates to GA

The feature to allow CSI Drivers to declare support for fsGroup based permissions graduates to GA in 1.23.

PodSecurity graduates to Beta

Container Runtime Interface (CRI) v1 is default

The Kubelet now supports the CRI v1 API, which is now the project-wide default. If a container runtime does not support the v1 API, Kubernetes will fall back to the v1alpha2 implementation. There is no intermediate action required by end-users, because v1 and v1alpha2 do not differ in their implementation. It is likely that v1alpha2 will be removed in one of the future Kubernetes releases to be able to develop v1.

Structured logging graduate to Beta

Structured logging reached its Beta milestone. Most log messages from kubelet and kube-scheduler have been converted. Users are encouraged to try out JSON output or parsing of the structured text format and provide feedback on possible solutions for the open issues, such as handling of multi-line strings in log values.

Simplified Multi-point plugin configuration for scheduler

The kube-scheduler is adding a new, simplified config field for Plugins to allow multiple extension points to be enabled in one spot. The new multiPoint plugin field is intended to simplify most scheduler setups for administrators. Plugins that are enabled via multiPoint will automatically be registered for each individual extension point that they implement. For example, a plugin that implements Score and Filter extensions can be simultaneously enabled for both. This means entire plugins can be enabled and disabled without having to manually edit individual extension point settings. These extension points can now be abstracted away due to their irrelevance for most users.

CSI Migration updates

CSI Migration enables the replacement of existing in-tree storage plugins such as kubernetes.io/gce-pd or kubernetes.io/aws-ebs with a corresponding CSI driver. If CSI Migration is working properly, Kubernetes end users shouldn’t notice a difference. After migration, Kubernetes users may continue to rely on all the functionality of in-tree storage plugins using the existing interface.

CSI Migration feature is turned on by default but stays in Beta for GCE PD, AWS EBS, and Azure Disk in 1.23.
CSI Migration is introduced as an Alpha feature for Ceph RBD and Portworx in 1.23.

Expression language validation for CRD is alpha

Expression language validation for CRD is in alpha starting in 1.23. If the CustomResourceValidationExpressions feature gate is enabled, custom resources will be validated by validation rules using the .

Server Side Field Validation is Alpha

If the ServerSideFieldValidation feature gate is enabled starting 1.23, users will receive warnings from the server when they send Kubernetes objects in the request that contain unknown or duplicate fields. Previously unknown fields and all but the last duplicate fields would be dropped by the server.

With the feature gate enabled, we also introduce the fieldValidation query parameter so that users can specify the desired behavior of the server on a per request basis. Valid values for the fieldValidation query parameter are:

Ignore (default when feature gate is disabled, same as pre-1.23 behavior of dropping/ignoring unkonwn fields)
Warn (default when feature gate is enabled).
Strict (this will fail the request with an Invalid Request error)

OpenAPI v3 is Alpha

If the OpenAPIV3 feature gate is enabled starting 1.23, users will be able to request the OpenAPI v3.0 spec for all Kubernetes types. OpenAPI v3 aims to be fully transparent and includes support for a set of fields that are dropped when publishing OpenAPI v2: default, nullable, oneOf, anyOf. A separate spec is published per Kubernetes group version (at the $cluster/openapi/v3/apis/<group>/<version> endpoint) for improved performance and discovery, for all group versions can be found at the $cluster/openapi/v3 path.

Other Updates

Graduated to Stable

Major Changes

Release Notes

Check out the full details of the Kubernetes 1.23 release in our .

Availability

Kubernetes 1.23 is available for download on kubeadm.

Release Team

This release was made possible by a very dedicated group of individuals, who came together as a team to deliver technical content, documentation, code, and a host of other components that go into every Kubernetes release.

A huge thank you to the release lead Rey Lejano for leading us through a successful release cycle, and to everyone else on the release team for supporting each other, and working so hard to deliver the 1.23 release for the community.

Release Theme and Logo

Kubernetes 1.23: The Next Frontier

"The Next Frontier" theme represents the new and graduated enhancements in 1.23, Kubernetes' history of Star Trek references, and the growth of community members in the release team.

Kubernetes has a history of Star Trek references. The original codename for Kubernetes within Google is Project 7, a reference to Seven of Nine from Star Trek Voyager. And of course Borg was the name for the predecessor to Kubernetes. "The Next Frontier" theme continues the Star Trek references. "The Next Frontier" is a fusion of two Star Trek titles, Star Trek V: The Final Frontier and Star Trek the Next Generation.

"The Next Frontier" represents a line in the SIG Release charter, "Ensure there is a consistent group of community members in place to support the release process across time." With each release team, we grow the community with new release team members and for many it's their first contribution in their open source frontier.

Reference: https://kubernetes.io/blog/2015/04/borg-predecessor-to-kubernetes/ Reference:

The Kubernetes 1.23 release logo continues with the theme's Star Trek reference. Every star is a helm from the Kubernetes logo. The ship represents the collective teamwork of the release team.

Rey Lejano designed the logo.

User Highlights

Check out how .

Using Kubernetes,

Ecosystem Updates

now available on-demand for anyone that would like to catch up!

Project Velocity

The CNCF K8s DevStats project aggregates a number of interesting data points related to the velocity of Kubernetes and various sub-projects. This includes everything from individual contributions to the number of companies that are contributing, and is an illustration of the depth and breadth of effort that goes into evolving this ecosystem.

In the v1.23 release cycle, which ran for 16 weeks (August 23 to December 7), we saw contributions from 1032 companies and 1084 individuals.

Event Update

here.
KubeCon + CloudNativeCon Europe 2022 will take place in Valencia, Spain, May 4 – 7, 2022! You can find more information about the conference and registration on the .

Kubernetes Community Days has upcoming events scheduled in Pakistan, Brazil, Chengdu, and in Australia.