_index [page]deterministic
Run this on any machine you wish to join an existing cluster
### Synopsis
When joining a kubeadm initialized cluster, we need to establish bidirectional trust. This is split into discovery (having the Node trust the Kubernetes Control Plane) and TLS bootstrap (having the Kubernetes Control Plane trust the Node).
There are 2 main schemes for discovery. The first is to use a shared token along with the IP address of the API server. The second is to provide a file - a subset of the standard kubeconfig file. The discovery/kubeconfig file supports token, client-go authentication plugins ("exec"), "tokenFile", and "authProvider". This file can be a local file or downloaded via an HTTPS URL. The forms are kubeadm join --discovery-token abcdef.1234567890abcdef 1.2.3.4:6443, kubeadm join --discovery-file path/to/file.conf, or kubeadm join --discovery-file https://url/file.conf. Only one form can be used. If the discovery information is loaded from a URL, HTTPS must be used. Also, in that case the host installed CA bundle is used to verify the connection.
If you use a shared token for discovery, you should also pass the --discovery-token-ca-cert-hash flag to validate the public key of the root certificate authority (CA) presented by the Kubernetes Control Plane. The value of this flag is specified as "<hash-type>:<hex-encoded-value>", where the supported hash type is "sha256". The hash is calculated over the bytes of the Subject Public Key Info (SPKI) object (as in RFC7469). This value is available in the output of "kubeadm init" or can be calculated using standard tools. The --discovery-token-ca-cert-hash flag may be repeated multiple times to allow more than one public key.
If you cannot know the CA public key hash ahead of time, you can pass the --discovery-token-unsafe-skip-ca-verification flag to disable this verification. This weakens the kubeadm security model since other nodes can potentially impersonate the Kubernetes Control Plane.
The TLS bootstrap mechanism is also driven via a shared token. This is used to temporarily authenticate with the Kubernetes Control Plane to submit a certificate signing request (CSR) for a locally created key pair. By default, kubeadm will set up the Kubernetes Control Plane to automatically approve these signing requests. This token is passed in with the --tls-bootstrap-token abcdef.1234567890abcdef flag.
Often times the same token is used for both parts. In this case, the --token flag can be used instead of specifying each token individually.
The "join [api-server-endpoint]" command executes the following phases: ``` preflight Run join pre-flight checks control-plane-prepare Prepare the machine for serving a control plane /download-certs Download certificates shared among control-plane nodes from the kubeadm-certs Secret /certs Generate the certificates for the new control plane components /kubeconfig Generate the kubeconfig for the new control plane components /control-plane Generate the manifests for the new control plane components kubelet-start Write kubelet settings, certificates and (re)start the kubelet etcd-join Join etcd for control plane nodes kubelet-wait-bootstrap Wait for the kubelet to bootstrap itself control-plane-join Join a machine as a control plane instance /mark-control-plane Mark a node as a control-plane wait-control-plane Wait for the control plane to start ```
``` kubeadm join [api-server-endpoint] [flags] ```
### Options
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<tr> <td colspan="2">--apiserver-advertise-address string</td> </tr> <tr> <td></td><td style="line-height: 130%; word-wrap: break-word;"><p>If the node should host a new control plane instance, the IP address the API Server will advertise it's listening on. If not set the defaul …(trimmed)