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kubeadm config

During kubeadm init, kubeadm uploads the ClusterConfiguration object to your cluster in a ConfigMap called kubeadm-config in the kube-system namespace. This configuration is then read during kubeadm join, kubeadm reset and kubeadm upgrade.

You can use kubeadm config print to print the default static configuration that kubeadm uses for kubeadm init and kubeadm join.

For more information on init and join navigate to Using kubeadm init with a configuration file or Using kubeadm join with a configuration file.

For more information on using the kubeadm configuration API navigate to Customizing components with the kubeadm API.

You can use kubeadm config migrate to convert your old configuration files that contain a deprecated API version to a newer, supported API version.

kubeadm config images list and kubeadm config images pull can be used to list and pull the images that kubeadm requires.

kubeadm config print

Print configuration

Synopsis

This command prints configurations for subcommands provided. For details, see: https://pkg.go.dev/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm#section-directories

kubeadm config print [flags]

Options

-h, --help

help for print

Options inherited from parent commands

--kubeconfig string     Default: "/etc/kubernetes/admin.conf"

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.

--rootfs string

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

kubeadm config print init-defaults

Print default init configuration, that can be used for 'kubeadm init'

Synopsis

This command prints objects such as the default init configuration that is used for 'kubeadm init'.

Note that sensitive values like the Bootstrap Token fields are replaced with placeholder values like "abcdef.0123456789abcdef" in order to pass validation but not perform the real computation for creating a token.

kubeadm config print init-defaults [flags]

Options

--component-configs strings

A comma-separated list for component config API objects to print the default values for. Available values: [KubeProxyConfiguration KubeletConfiguration]. If this flag is not set, no component configs will be printed.

-h, --help

help for init-defaults

Options inherited from parent commands

--kubeconfig string     Default: "/etc/kubernetes/admin.conf"

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.

--rootfs string

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

kubeadm config print join-defaults

Print default join configuration, that can be used for 'kubeadm join'

Synopsis

This command prints objects such as the default join configuration that is used for 'kubeadm join'.

Note that sensitive values like the Bootstrap Token fields are replaced with placeholder values like "abcdef.0123456789abcdef" in order to pass validation but not perform the real computation for creating a token.

kubeadm config print join-defaults [flags]

Options

--component-configs strings

A comma-separated list for component config API objects to print the default values for. Available values: [KubeProxyConfiguration KubeletConfiguration]. If this flag is not set, no component configs will be printed.

-h, --help

help for join-defaults

Options inherited from parent commands

--kubeconfig string     Default: "/etc/kubernetes/admin.conf"

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.

--rootfs string

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

kubeadm config migrate

Read an older version of the kubeadm configuration API types from a file, and output the similar config object for the newer version

Synopsis

This command lets you convert configuration objects of older versions to the latest supported version, locally in the CLI tool without ever touching anything in the cluster. In this version of kubeadm, the following API versions are supported:

  • kubeadm.k8s.io/v1beta3

Further, kubeadm can only write out config of version "kubeadm.k8s.io/v1beta3", but read both types. So regardless of what version you pass to the --old-config parameter here, the API object will be read, deserialized, defaulted, converted, validated, and re-serialized when written to stdout or --new-config if specified.

In other words, the output of this command is what kubeadm actually would read internally if you submitted this file to "kubeadm init"

kubeadm config migrate [flags]

Options

-h, --help

help for migrate

--new-config string

Path to the resulting equivalent kubeadm config file using the new API version. Optional, if not specified output will be sent to STDOUT.

--old-config string

Path to the kubeadm config file that is using an old API version and should be converted. This flag is mandatory.

Options inherited from parent commands

--kubeconfig string     Default: "/etc/kubernetes/admin.conf"

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.

--rootfs string

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

kubeadm config images list

Print a list of images kubeadm will use. The configuration file is used in case any images or image repositories are customized

Synopsis

Print a list of images kubeadm will use. The configuration file is used in case any images or image repositories are customized

kubeadm config images list [flags]

Options

--allow-missing-template-keys     Default: true

If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats.

--config string

Path to a kubeadm configuration file.

-o, --experimental-output string     Default: "text"

Output format. One of: text|json|yaml|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-as-json|jsonpath-file.

--feature-gates string

A set of key=value pairs that describe feature gates for various features. Options are:
PublicKeysECDSA=true|false (ALPHA - default=false)
RootlessControlPlane=true|false (ALPHA - default=false)
UnversionedKubeletConfigMap=true|false (default=true)

-h, --help

help for list

--image-repository string     Default: "registry.k8s.io"

Choose a container registry to pull control plane images from

--kubernetes-version string     Default: "stable-1"

Choose a specific Kubernetes version for the control plane.

--show-managed-fields

If true, keep the managedFields when printing objects in JSON or YAML format.

Options inherited from parent commands

--kubeconfig string     Default: "/etc/kubernetes/admin.conf"

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.

--rootfs string

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

kubeadm config images pull

Pull images used by kubeadm

Synopsis

Pull images used by kubeadm

kubeadm config images pull [flags]

Options

--config string

Path to a kubeadm configuration file.

--cri-socket string

Path to the CRI socket to connect. If empty kubeadm will try to auto-detect this value; use this option only if you have more than one CRI installed or if you have non-standard CRI socket.

--feature-gates string

A set of key=value pairs that describe feature gates for various features. Options are:
PublicKeysECDSA=true|false (ALPHA - default=false)
RootlessControlPlane=true|false (ALPHA - default=false)
UnversionedKubeletConfigMap=true|false (default=true)

-h, --help

help for pull

--image-repository string     Default: "registry.k8s.io"

Choose a container registry to pull control plane images from

--kubernetes-version string     Default: "stable-1"

Choose a specific Kubernetes version for the control plane.

Options inherited from parent commands

--kubeconfig string     Default: "/etc/kubernetes/admin.conf"

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.

--rootfs string

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

What's next

Last modified October 27, 2021 at 12:32 AM PST: kubeadm-config.md: update the page to reflect current state (586b359b05)