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Container Service for Kubernetes:Support for Kubernetes versions

Last Updated:Jun 05, 2024

Container Service for Kubernetes (ACK) provides container-centric solutions based on open source Kubernetes. As new Kubernetes versions are released, the list of Kubernetes versions supported by ACK also changes. New Kubernetes versions will be added to the list and outdated Kubernetes versions will be discontinued. This topic describes how ACK supports different Kubernetes versions, including the version list update cycle, the support policies, and the risks of using outdated Kubernetes versions.

Release history

The following table describes the Kubernetes versions that are supported by ACK clusters and ACK Serverless clusters.

Version

Status

Release date (ACK)

Discontinue date (ACK)

1.30

Released

June 2024

June 2026

1.28

Released

October 2023

October 2025

1.26

Released

April 2023

April 2025

1.24

Released

September 2022

September 2024

1.22

Discontinued

December 2021

October 2023

1.20

Discontinued

April 2021

April 2023

1.18

Discontinued

September 2020

September 2022

1.16

Discontinued

February 2020

June 2022

1.14

Discontinued

August 2019

July 2021

1.12

Discontinued

March 2019

December 2020

Version updates

Starting from January 1, 2020, ACK supports only even-numbered Kubernetes minor versions, such as 1.24, 1.26, and 1.28.

After the Kubernetes community releases a new even-numbered minor version, ACK performs a risk assessment and consistency test on the version, and then allows you to create clusters of the new version and upgrade existing clusters to the new version. In most cases, the preparations take two weeks and the duration varies depending on the differences between versions.

After the Kubernetes community releases a new patch version for an even-numbered minor version, ACK determines whether to release the patch version based on the risk level of the issue fixed by the patch version. In most cases, ACK requires about 24 hours to perform a risk assessment and consistency test on a patch version that fixes critical issues, such as high-risk security vulnerabilities. Then, ACK allows you to create clusters of the new version and upgrade existing clusters to the new version.

Version description

The Kubernetes versions supported by ACK follow the semantic versioning scheme in the x.y.z-aliyun.n format. x.y.z is the open source Kubernetes version. x is the major version, y is the minor version, z is the patch version, and n is the ACK patch version. For example, version 1.28.3-aliyun.1 is based on open source Kubernetes 1.28.3. For more information about Kubernetes versions, see Kubernetes Release Versioning.

Rules for supporting Kubernetes versions

  • Cluster creation

    ACK allows you to create clusters of the latest three even-numbered minor versions. For example, if the latest minor version is 1.28, you can create clusters of 1.24, 1.26, and 1.28. When ACK starts to support 1.28, 1.22 is discontinued and you can no longer create clusters of 1.22. In addition, the outdated patch version is no longer available.

  • Cluster update

    ACK allows you to update ACK clusters from a minor version to the following minor version. You cannot skip minor versions when you update ACK clusters or roll back your ACK clusters to an earlier version. For example, if your cluster version is 1.24 and you want to update the cluster to 1.28, you need to complete the update in two steps. You need to update the cluster to 1.26 and then update it to 1.28.

    For patch versions, ACK allows you to update an ACK cluster only to the latest patch version. You cannot update your cluster to outdated patch versions.

  • Technical support

    Alibaba Cloud provides technical support for the latest three even-numbered minor versions. Technical support provided by Alibaba Cloud includes consultation, online tutorials, and troubleshooting.

Outdated Kubernetes versions

Security and stability risks exist in outdated Kubernetes versions. We recommend that you update your clusters that use outdated Kubernetes versions at the earliest opportunity. For more information about cluster updates, see Manually update ACK clusters.

ACK provides the following support policies for clusters that run outdated Kubernetes versions:

  • Stop releasing new features

  • Stop fixing feature and security issues

  • Provide limited technical support

    ACK does not guarantee that technical support can be provided at the first time except for issues related to cluster and component updates.

  • Reserve the right to force the clusters that run outdated Kubernetes versions to update

    For availability and security purposes, after the Kubernetes version of a cluster becomes outdated, ACK forces the cluster to update to the earliest Kubernetes version supported by ACK. For example, if your cluster version is 1.20 and ACK supports Kubernetes versions 1.24, 1.26, and 1.28, ACK forces your cluster to update to 1.24.

    ACK will send notifications to you by text messages, emails, or internal messages at least one month before the update. Pay close attention to the notifications and prepare for the update in advance.

References

We recommend that you learn the updates and usage notes of each Kubernetes version before you update your cluster. For more information about cluster updates, see Manually update ACK clusters.