In v1.15.0, kubeadm introduced preliminary support for kubeadm upgrade node phases. Phases for other kubeadm upgrade sub-commands such as apply, could be added in the following releases.
kubeadm upgrade node phase
Using this phase you can choose to execute the separate steps of the upgrade of secondary control-plane or worker nodes. Please note that kubeadm upgrade apply still has to be called on a primary control-plane node.
The kubeconfig file to use when talking to the cluster. If the flag is not set, a set of standard locations can be searched for an existing kubeconfig file.
Options inherited from parent commands
[EXPERIMENTAL] The path to the 'real' host root filesystem.
Download the kubelet configuration from a ConfigMap of the form “kubelet-config-1.X” in the cluster, where X is the minor version of the kubelet. kubeadm uses the KuberneteVersion field in the kubeadm-config ConfigMap to determine what the desired kubelet version is, but the user can override this by using the –kubelet-version parameter.
kubeadm upgrade node phase kubelet-config [flags]
Do not change any state, just output the actions that would be performed.