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Kubernetes Removals and Deprecations In 1.24

Thursday, March 31, 2022

Authors: Mickey Boxell (Oracle), Debabrata Panigrahi (Independent)

As Kubernetes evolves, features and APIs are periodically revisited and removed. New features may offer an alternative or improved approach to solving an existing problem, motivating the team to remove the old method. Rather than immediately being removed, old APIs are first deprecated and then removed according to the Kubernetes Deprecation Policy.

We want to make sure you are aware of the changes coming in the Kubernetes 1.24 release. Kubernetes 1.24 is scheduled to be released in April and includes several removed and deprecated APIs. Removed APIs are those that you can use in current, supported Kubernetes versions but have already been deprecated. These removals have been superseded by newer, stable/generally available (GA) APIs. Deprecated APIs have been marked for removal in a future Kubernetes release.

For an exhaustive list of the changes coming in Kubernetes 1.24, take a look at the CHANGELOG.

API removals and deprecations for Kubernetes 1.24

Removals

The 1.24 release will stop serving the API versions listed below.

Deprecations

The 1.24 release deprecates the API versions listed below.

A note about Dockershim

It's safe to say that the removal receiving the most attention with the release of Kubernetes 1.24 is Dockershim. Dockershim was deprecated in 1.20. As noted in the Kubernetes 1.20 changelog: "Docker support in the kubelet is now deprecated and will be removed in a future release. The kubelet uses a module called "dockershim" which implements CRI support for Docker and it has seen maintenance issues in the Kubernetes community." With the upcoming release of Kubernetes 1.24, that day is finally here.

In the article, Don't Panic: Kubernetes and Docker, the authors succinctly captured the change's impact and encouraged users to remain calm: "Docker as an underlying runtime is being deprecated in favor of runtimes that use the Container Runtime Interface (CRI) created for Kubernetes. Docker-produced images will continue to work in your cluster with all runtimes, as they always have." Several guides have been created with helpful information about migrating from dockershim to other container runtimes. You can find them on the Migrating from dockershim page in the Kubernetes documentation.

For more information about why Kubernetes is moving away from dockershim, check out the aptly named: Kubernetes is Moving on From Dockershim and the updated dockershim removal FAQ.

Take a look at the What you need to do to have a working cluster for 1.24 to learn what you need to do to go from a working 1.23 cluster to a working 1.24 cluster.

What to do

kubectl convert

As mentioned in prior API removal posts, kubectl-convert, a plugin for the kubectl Kubernetes command-line tool, can be helpful to address migrating off deprecated APIs. It does so by facilitating the conversion of manifests between different API versions, for example, from a deprecated to a non-deprecated API version. More general information about the API migration process can be found in the Deprecated API Migration Guide.

The Kubernetes API removal process

Kubernetes contains a large number of components that evolve over time. In some cases, this evolution results in APIs, flags, or entire features, being removed. To prevent users from facing breaking changes, Kubernetes adopted a feature deprecation policy. This policy ensures that stable APIs may only be deprecated when a newer stable version of that same API is available and that APIs have a minimum lifetime depending on their stability level:

  • Generally available (GA) or stable API versions may be marked as deprecated but must not be removed within a major version of Kubernetes.
  • Beta or pre-release API versions must be supported for 3 releases after deprecation.
  • Alpha or experimental API versions may be removed in any release without prior deprecation notice.

Kubernetes will continue to remove APIs by following the deprecation policy regardless of whether an API is removed due to a beta feature graduating to stable or because that API was not proven to be successful and will also make sure migration options are documented.

Looking ahead

The Kubernetes 1.25 and 1.26 releases planned for later this year will stop serving beta versions of several currently stable Kubernetes APIs. The 1.25 release will also remove PodSecurityPolicy, which was deprecated with Kubernetes 1.21 and will not graduate to stable. See PodSecurityPolicy Deprecation: Past, Present, and Future for more information.

The official list of API removals planned for Kubernetes 1.25 is:

  • The beta CronJob API (batch/v1beta1)
  • The beta EndpointSlice API (discovery.k8s.io/v1beta1)
  • The beta Event API (events.k8s.io/v1beta1)
  • The beta HorizontalPodAutoscaler API (autoscaling/v2beta1)
  • The beta PodDisruptionBudget API (policy/v1beta1)
  • The beta PodSecurityPolicy API (policy/v1beta1)
  • The beta RuntimeClass API (node.k8s.io/v1beta1)

The official list of API removals planned for Kubernetes 1.26 is:

Want to know more?

Deprecations are announced in the Kubernetes release notes. You can see the announcements of pending deprecations in the release notes for:

For information on the process of deprecation and removal, check out the official Kubernetes deprecation policy document.

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Kubernetes 1.24 Release Team
Kubernetes 1.24 Release Team
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Kubernetes 1.24 Authors: Kubernetes 1.24 Release Team We are excited to announce the release of Kubernetes 1.24, the first release of 2022! This release consists of 46 enhancements: 15 enhancements have graduated to stable, 15 enhancements are moving to beta, and 13 enhancements are entering alpha. Also, 2 features have been deprecated, and the dockershim has been removed. Major Themes Dockershim Removed from kubelet Following a deprecation period that started with the v1.20 release, Kubernetes no longer includes the dockershim adapter. If you have been relying on Docker Engine as your container runtime, you will need to either switch to using a different supported container runtime (such as containerd or CRI-O), or use continue to use Docker Engine but via an adapter such as cri-dockerd.

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