Upgrading Kubernetes Worker Nodes
Although Kubernetes supports compatibility between master (API server) and worker nodes (kubelet) within one minor version, it is highly recommended that you upgrade the master and worker nodes in one go. Using kops, upgrading worker nodes is similar to upgrading master nodes. Due to the backward compatibility within one minor version, the worker nodes may still work if they are not version-matched by the master nodes, but it is strongly discouraged to run different versions of Kubernetes on worker and master nodes since this may create problems for the cluster.
However, the following considerations are of extreme importance if you want to keep your application online during the upgrade:
- Make sure that your applications are configured to be highly available. This means that you should have at least two pods, each on different nodes, for each of your applications. If this is not the case, your applications may experience downtime once you...