Upgrade A Cluster

    The way that you upgrade a cluster depends on how you initially deployed it and on any subsequent changes.

    At a high level, the steps you perform are:

    • Upgrade the control plane
    • Upgrade the nodes in your cluster
    • Adjust manifests and other resources based on the API changes that accompany the new Kubernetes version

    You must have an existing cluster. This page is about upgrading from Kubernetes 1.26 to Kubernetes 1.27. If your cluster is not currently running Kubernetes 1.26 then please check the documentation for the version of Kubernetes that you plan to upgrade to.

    If your cluster was deployed using the tool, refer to Upgrading kubeadm clusters for detailed information on how to upgrade the cluster.

    Once you have upgraded the cluster, remember to .

    Manual deployments

    You should manually update the control plane following this sequence:

    • etcd (all instances)
    • kube-apiserver (all control plane hosts)
    • kube-controller-manager
    • kube-scheduler

    At this point you should .

    For each node in your cluster, drain that node and then either replace it with a new node that uses the 1.27 kubelet, or upgrade the kubelet on that node and bring the node back into service.

    Refer to the documentation for your cluster deployment tool to learn the recommended set up steps for maintenance.

    Switch your cluster’s storage API version

    The objects that are serialized into etcd for a cluster’s internal representation of the Kubernetes resources active in the cluster are written using a particular version of the API.

    For each affected object, fetch it using the latest supported API and then write it back also using the latest supported API.

    Upgrading to a new Kubernetes version can provide new APIs.

    You can use kubectl convert command to convert manifests between different API versions. For example:

    The tool replaces the contents of pod.yaml with a manifest that sets to Pod (unchanged), but with a revised apiVersion.

    Device Plugins

    If your cluster is running device plugins and the node needs to be upgraded to a Kubernetes release with a newer device plugin API version, device plugins must be upgraded to support both version before the node is upgraded in order to guarantee that device allocations continue to complete successfully during the upgrade.