website/content/en/docs/reference/setup-tools/kubeadm/generated/kubeadm_token.md

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Synopsis

This command manages bootstrap tokens. It is optional and needed only for advanced use cases.

In short, bootstrap tokens are used for establishing bidirectional trust between a client and a server. A bootstrap token can be used when a client (for example a node that is about to join the cluster) needs to trust the server it is talking to. Then a bootstrap token with the "signing" usage can be used. bootstrap tokens can also function as a way to allow short-lived authentication to the API Server (the token serves as a way for the API Server to trust the client), for example for doing the TLS Bootstrap.

What is a bootstrap token more exactly?

  • It is a Secret in the kube-system namespace of type "bootstrap.kubernetes.io/token".
  • A bootstrap token must be of the form "[a-z0-9]{6}.[a-z0-9]{16}". The former part is the public token ID, while the latter is the Token Secret and it must be kept private at all circumstances!
  • The name of the Secret must be named "bootstrap-token-(token-id)".

You can read more about bootstrap tokens here: https://kubernetes.io/docs/admin/bootstrap-tokens/

kubeadm token [flags]

Options

<tr>
  <td colspan="2">--dry-run</td>
</tr>
<tr>
  <td></td><td style="line-height: 130%; word-wrap: break-word;">Whether to enable dry-run mode or not</td>
</tr>

<tr>
  <td colspan="2">-h, --help</td>
</tr>
<tr>
  <td></td><td style="line-height: 130%; word-wrap: break-word;">help for token</td>
</tr>

<tr>
  <td colspan="2">--kubeconfig string&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Default: "/etc/kubernetes/admin.conf"</td>
</tr>
<tr>
  <td></td><td style="line-height: 130%; word-wrap: break-word;">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.</td>
</tr>

Options inherited from parent commands

<tr>
  <td colspan="2">--rootfs string</td>
</tr>
<tr>
  <td></td><td style="line-height: 130%; word-wrap: break-word;">[EXPERIMENTAL] The path to the 'real' host root filesystem.</td>
</tr>