kubeadm

kubeadm is the Kubernetes project's own tool for turning a set of existing Linux machines into a working cluster. Running kubeadm init sets up a control-plane node, and kubeadm join adds worker nodes. Other subcommands handle version upgrades, join tokens, certificate management, kubeconfig files and resetting a node. The tool is general availability, but anything under kubeadm alpha is still alpha-level. It is maintained by the Cluster Lifecycle SIG under the Apache 2.0 license. Its scope is deliberately narrow. It does not provision machines and does not install addons such as a dashboard, monitoring, cloud integrations, a network plugin, a storage provisioner or load balancers. Higher-level installers are often built on top of it for this reason. It suits platform and IT teams that want standard upstream Kubernetes on bare metal, in private data centers, in air-gapped sites or in hybrid setups, and engineers studying for the CKA exam. There is no license fee and no paid tier. The real costs are the infrastructure you supply and the staff time to run it. Each machine needs a deb or rpm-based Linux distribution and at least 2 GiB of RAM, and control-plane nodes need at least 2 CPUs. Because it produces conformant clusters, standard Kubernetes tooling and CNI plugins work with it. The main limitation is operational effort. Upgrades run node by node, there is no cloud lifecycle management, and there is no vendor support or SLA, so teams that want less work usually choose a managed service or a lighter distribution such as k3s.