Learn Kubernetes Basics

Reference

Kubernetes v1.15 documentation is no longer actively maintained. The version you are currently viewing is a static snapshot. For up-to-date documentation, see the latest version.

Edit This Page

kubeadm alpha

Caution: kubeadm alpha provides a preview of a set of features made available for gathering feedback from the community. Please try it out and give us feedback!

kubeadm alpha certs renew

You can renew all Kubernetes certificates using the all subcommand or renew them selectively. For more details about certificate expiration and renewal see the certificate management documentation.

Renew certificates for a Kubernetes cluster

Synopsis

This command is not meant to be run on its own. See list of available subcommands.

kubeadm alpha certs renew [flags]

Options

  -h, --help   help for renew

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew all available certificates

Synopsis

Renew all known certificates necessary to run the control plane. Renewals are run unconditionally, regardless of expiration date. Renewals can also be run individually for more control.

kubeadm alpha certs renew all [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for all
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate embedded in the kubeconfig file for the admin to use and for kubeadm itself

Synopsis

Renew the certificate embedded in the kubeconfig file for the admin to use and for kubeadm itself.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew admin.conf [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for admin.conf
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate the apiserver uses to access etcd

Synopsis

Renew the certificate the apiserver uses to access etcd.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew apiserver-etcd-client [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for apiserver-etcd-client
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate for the API server to connect to kubelet

Synopsis

Renew the certificate for the API server to connect to kubelet.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew apiserver-kubelet-client [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for apiserver-kubelet-client
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate for serving the Kubernetes API

Synopsis

Renew the certificate for serving the Kubernetes API.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew apiserver [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for apiserver
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate embedded in the kubeconfig file for the controller manager to use

Synopsis

Renew the certificate embedded in the kubeconfig file for the controller manager to use.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew controller-manager.conf [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for controller-manager.conf
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate for liveness probes to healtcheck etcd

Synopsis

Renew the certificate for liveness probes to healtcheck etcd.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew etcd-healthcheck-client [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for etcd-healthcheck-client
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate for etcd nodes to communicate with each other

Synopsis

Renew the certificate for etcd nodes to communicate with each other.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew etcd-peer [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for etcd-peer
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate for serving etcd

Synopsis

Renew the certificate for serving etcd.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew etcd-server [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for etcd-server
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate for the front proxy client

Synopsis

Renew the certificate for the front proxy client.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew front-proxy-client [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for front-proxy-client
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Renew the certificate embedded in the kubeconfig file for the scheduler manager to use

Synopsis

Renew the certificate embedded in the kubeconfig file for the scheduler manager to use.

Renewals run unconditionally, regardless of certificate expiration date; extra attributes such as SANs will be based on the existing file/certificates, there is no need to resupply them.

Renewal by default tries to use the certificate authority in the local PKI managed by kubeadm; as alternative it is possible to use K8s certificate API for certificate renewal, or as a last option, to generate a CSR request.

After renewal, in order to make changes effective, is is required to restart control-plane components and eventually re-distribute the renewed certificate in case the file is used elsewhere.

kubeadm alpha certs renew scheduler.conf [flags]

Options

      --cert-dir string     The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string       Path to a kubeadm configuration file.
      --csr-dir string      The path to output the CSRs and private keys to
      --csr-only            Create CSRs instead of generating certificates
  -h, --help                help for scheduler.conf
      --kubeconfig string   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. (default "/etc/kubernetes/admin.conf")
      --use-api             Use the Kubernetes certificate API to renew certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

kubeadm alpha certs certificate-key

This command can be used to generate a new control-plane certificate key. The key can be passed as --certificate-key to kubeadm init and kubeadm join to enable the automatic copy of certificates when joining additional control-plane nodes.

Generate certificate keys

Synopsis

This command will print out a secure randomly-generated certificate key that can be used with the “init” command.

You can also use “kubeadm init –experimental-upload-certs” without specifying a certificate key and it will generate and print one for you.

kubeadm alpha certs certificate-key [flags]

Options

  -h, --help   help for certificate-key

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

kubeadm alpha certs check-expiration

This command checks expiration for the certificates in the local PKI managed by kubeadm. For more details about certificate expiration and renewal see the certificate management documentation.

Check certificates expiration for a Kubernetes cluster

Synopsis

Checks expiration for the certificates in the local PKI managed by kubeadm.

kubeadm alpha certs check-expiration [flags]

Options

      --cert-dir string   The path where to save the certificates (default "/etc/kubernetes/pki")
      --config string     Path to a kubeadm configuration file.
  -h, --help              help for check-expiration

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

kubeadm alpha kubeconfig user

The user subcommand can be used for the creation of kubeconfig files for additional users.

Kubeconfig file utilities

Synopsis

Kubeconfig file utilities.

Alpha Disclaimer: this command is currently alpha.

Options

  -h, --help   help for kubeconfig

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Output a kubeconfig file for an additional user

Synopsis

Output a kubeconfig file for an additional user.

Alpha Disclaimer: this command is currently alpha.

kubeadm alpha kubeconfig user [flags]

Examples

  # Output a kubeconfig file for an additional user named foo
  kubeadm alpha kubeconfig user --client-name=foo

Options

      --apiserver-advertise-address string   The IP address the API server is accessible on
      --apiserver-bind-port int32            The port the API server is accessible on (default 6443)
      --cert-dir string                      The path where certificates are stored (default "/etc/kubernetes/pki")
      --client-name string                   The name of user. It will be used as the CN if client certificates are created
  -h, --help                                 help for user
      --org strings                          The orgnizations of the client certificate. It will be used as the O if client certificates are created
      --token string                         The token that should be used as the authentication mechanism for this kubeconfig, instead of client certificates

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

kubeadm alpha kubelet config

Use the following commands to either download the kubelet configuration from the cluster or to enable the DynamicKubeletConfiguration feature.

Commands related to handling the kubelet

Synopsis

This command is not meant to be run on its own. See list of available subcommands.

Options

  -h, --help   help for kubelet

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Download the kubelet configuration from the cluster ConfigMap kubelet-config-1.X, where X is the minor version of the kubelet

Synopsis

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. Either kubeadm autodetects the kubelet version by exec-ing “kubelet –version” or respects the –kubelet-version parameter.

Alpha Disclaimer: this command is currently alpha.

kubeadm alpha kubelet config download [flags]

Examples

  # Download the kubelet configuration from the ConfigMap in the cluster. Autodetect the kubelet version.
  kubeadm alpha phase kubelet config download
  
  # Download the kubelet configuration from the ConfigMap in the cluster. Use a specific desired kubelet version.
  kubeadm alpha phase kubelet config download --kubelet-version 1.14.0

Options

  -h, --help                     help for download
      --kubeconfig string        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. (default "/etc/kubernetes/admin.conf")
      --kubelet-version string   The desired version for the kubelet. Defaults to being autodetected from 'kubelet --version'.

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Download the kubelet configuration from the cluster ConfigMap kubelet-config-1.X, where X is the minor version of the kubelet

Synopsis

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. Either kubeadm autodetects the kubelet version by exec-ing “kubelet –version” or respects the –kubelet-version parameter.

Alpha Disclaimer: this command is currently alpha.

kubeadm alpha kubelet config download [flags]

Examples

  # Download the kubelet configuration from the ConfigMap in the cluster. Autodetect the kubelet version.
  kubeadm alpha phase kubelet config download
  
  # Download the kubelet configuration from the ConfigMap in the cluster. Use a specific desired kubelet version.
  kubeadm alpha phase kubelet config download --kubelet-version 1.14.0

Options

  -h, --help                     help for download
      --kubeconfig string        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. (default "/etc/kubernetes/admin.conf")
      --kubelet-version string   The desired version for the kubelet. Defaults to being autodetected from 'kubelet --version'.

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

kubeadm alpha selfhosting pivot

The subcommand pivot can be used to convert a static Pod-hosted control plane into a self-hosted one.

Documentation

Make a kubeadm cluster self-hosted

Synopsis

This command is not meant to be run on its own. See list of available subcommands.

Options

  -h, --help   help for selfhosting

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

Convert a static Pod-hosted control plane into a self-hosted one

Synopsis

Convert static Pod files for control plane components into self-hosted DaemonSets configured via the Kubernetes API.

See the documentation for self-hosting limitations.

Alpha Disclaimer: this command is currently alpha.

kubeadm alpha selfhosting pivot [flags]

Examples

  # Convert a static Pod-hosted control plane into a self-hosted one.
  
  kubeadm alpha phase self-hosting convert-from-staticpods

Options

      --cert-dir string          The path where certificates are stored (default "/etc/kubernetes/pki")
      --config string            Path to a kubeadm configuration file.
  -f, --force                    Pivot the cluster without prompting for confirmation
  -h, --help                     help for pivot
      --kubeconfig string        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. (default "/etc/kubernetes/admin.conf")
  -s, --store-certs-in-secrets   Enable storing certs in secrets

Options inherited from parent commands

      --rootfs string   [EXPERIMENTAL] The path to the 'real' host root filesystem.

What’s next

Feedback