We have some workloads running on GKE. They got deployed in early 2020 and have not really been touched since then.

Google has sent us instructions for upgrading, however we don't want to, because the workload is only going to be used for some further months.

My question is, what happens to clusters with older versions of Kubernetes in case they can not be auto-upgraded, as in our case? We assume that they will simply continue to run, however we need confirmation. Auto-upgrade is not possible because we have the docker runtime and that is not compatible with newer containerd runtimes, which are used now in the current versions of GKE.

Anyone has any experience with this situation?

CodePudding user response：

GKE will most definitely upgrade both the control plane and worker nodes. As of the latest release, 1.18 clusters will be upgraded to 1.19.16-gke.8300 which will go end of life in June, 2022. 1.19 still has the Docker runtime so there should be no issues there.

CodePudding user response：

If you do not upgrade off v1.18, you will forcibly upgraded to the last supported stable version when Google ceases support of v1.18. This happened to us (not on 1.18, but the same situation) and although it didn't break any workloads until we had to update them after the upgrade.

Your nodes may hang onto 1.18 a bit longer, based on your auto-upgrade setting for your node pools.