Kubernetes community releases a minor version about every three months. In those minor version releases, there are some new features and bug fixes. Patch versions will be released more frequent (e.g. weekly) and genereally to include critical fixes , e.g. security fixes.
Catalyst Cloud Kubernetes Service supports each
minor version for at least
9 months before deprecating it to give users enough time to upgrade their
clusters. The 9 months is calculated based on that the Kubernetes community
maintains release branches for the latest 3 minor versions and they release a
new mintor version about every three months. User will get support from
Catalyst Cloud to any patch and date version within these releases.
Kubernetes follows the standard Semantic Versioning terminology. Versions are expressed as x.y.z, where x is the major version, y is the minor version and z is the patch version.
versions that may make incompatible API changes
versions that adds functionality in a backwards compatible manner
versions that makes backwards compatible bug fixes
[major].[minor].[patch] v1.18.2 v1.17.5 v1.16.9
Catalyst Cloud Kubernetes Service uses cluster template to manage each Kubernetes version and the matrix of addons that running on top of Kubernetes cluster. And users should be able to see the Kubernetes version from the cluster template name. For example: kubernetes-v1.16.9-prod-20200602, the last 8 digits is the release date of this template tagged by Catalyst Cloud.
For more information, see Kubernetes Release Versioning.
Catalyst Cloud Kubernetes Service supports at least
3 minors versions. As long
as there is a new minor version released, Catalyst Cloud Kubernetes Service will
try to get it certified (pass the CNCF conformance test) and released in
days. And then deprecate the oldest minor version. For example, if the current
3 minor versions are v1.17.x, v1.16.x and v1.15.x. Then as long as the new
v1.18.x released, the version v1.15.x will be removed and out of supported.
Out of support means whenever users ask for support, you will be asked
to upgrade your clusters to supported versions first. In short, if the cluster
is running on a minor version which has been deprecated, then the cluster is
out of support.
Catalyst Cloud Kubernetes Service supports the latest stable patch versions for each minor version. As long as there is a patch version released, the oldest patch version will be hidded/removed. For example, if current versions supported for v1.16.x are v1.16.9, then v1.16.9 will be hidded/removed in favor of the release of v1.16.10.
For clarity, hidding a
patch version/template doesn’t mean it is out of
support, it means we are motivating customers to always use the latest one.
If there is a bug impacting customers on the latest patch version we would
either unhide the previous version or publish a new patch version.
Users should always aim to run the latest patch version for each minor version to get the latest security enhancements. For example, if the current Kubernetes cluster is running on v1.16.9 and the new patch version is v1.16.10, then it is highly recommended to upgrade to v1.16.10 as soon as possible.
Catalyst Cloud reserves the right to add/remove a new/existing cluster template if there is a cirtical issue identified in the version without further notice.
When doing Kubernetes version upgrade, minor vesion cannot be skipped. For example, if the current cluster version is v1.16.x, then it’s not allowed to upgrade to v1.18.x. You have to upgrade to v1.17.x and then do another upgrade to v1.18.x.
Catalyst Cloud reserves the right to do a force patch version upgrade if there is an urgent critical security vulnerbility (CVE rated as high) and the customer cannot be reached.
Catalyst Cloud Kubernetes Service is using Fedora CoreOS as the Kubernetes Node operating system, the original image will be updated regularly. We’re using Podman and systemd to manage all the Kubernetes components and using Docker for the container runtime of Kubernetes.
Node Operating System: Fedora CoreOS 31
The only supported CNI on Catalyst Cloud Kubernetes Service is Calico and the current versions is v3.13.1.
At this stage, Catalyst Cloud Kubernetes Service doesn’t support upgrade the addons’ versions, such as Calico, CoreDNS etc.