kubeadm

Initialize control plane

$ sudo kubeadm init

$ sudo kubeadm join [control-plane:6443] --token [token] --discovery-token-ca-cert-hash [hash]

$ kubeadm token create --print-join-command

$ sudo kubeadm reset

$ sudo kubeadm upgrade apply [v1.28.0]

$ kubeadm config print init-defaults

kubeadm command [options]

kubeadm is the official Kubernetes cluster bootstrapping tool that automates the setup of a production-grade control plane. It handles the complex initialization process including generating TLS certificates for cluster components, configuring the kubelet, deploying the kube-apiserver, kube-controller-manager, and kube-scheduler as static pods, and installing cluster-essential add-ons like CoreDNS and kube-proxy.
The workflow centers on two primary commands: `kubeadm init` to create a new control plane on the first node, and `kubeadm join` to add worker nodes or additional control plane nodes to an existing cluster using bootstrap tokens. The tool also manages cluster lifecycle operations such as upgrading Kubernetes versions across the cluster, rotating certificates, and resetting nodes back to a clean state.
kubeadm follows Kubernetes best practices and conformance standards, but intentionally does not provision the underlying infrastructure or install a CNI network plugin, keeping it focused on cluster bootstrapping while remaining composable with other tools for complete cluster management.

init

Initialize control plane.

Join cluster as node.

Reset node to pre-init state.

Upgrade cluster components.

Manage join tokens.

Manage configuration.

Display help information.

Requires root. Container runtime needed. Network plugin not included.

kubeadm was created as the official cluster bootstrapping tool for Kubernetes, simplifying cluster setup.

kubectl(1), kubelet(8), kops(1)