token is used for establishing bidirectional trust between nodes and control-planes. Used for joining nodes in the cluster.

description sets a human-friendly message why this token exists and what it’s used for, so other administrators can know its purpose.

ttl defines the time to live for this token. Defaults to 24h. expires and ttl are mutually exclusive.

expires specifies the timestamp when this token expires. Defaults to being set dynamically at runtime based on the ttl. expires and ttl are mutually exclusive.

usages describes the ways in which this token can be used. Can by default be used for establishing bidirectional trust, but that can be changed here.

groups specifies the extra groups that this token will authenticate as when/if used for authentication

etcd holds the configuration for etcd.

networking holds configuration for the networking topology of the cluster.

kubernetesVersion is the target version of the control plane.

controlPlaneEndpoint sets a stable IP address or DNS name for the control plane; It can be a valid IP address or a RFC-1123 DNS subdomain, both with optional TCP port. In case the controlPlaneEndpoint is not specified, the advertiseAddress + bindPort are used; in case the controlPlaneEndpoint is specified but without a TCP port, the bindPort is used. Possible usages are:

• In a cluster with more than one control plane instances, this field should be assigned the address of the external load balancer in front of the control plane instances.
• In environments with enforced node recycling, the controlPlaneEndpoint could be used for assigning a stable DNS to the control plane.

apiServer contains extra settings for the API server.

controllerManager contains extra settings for the controller manager.

scheduler contains extra settings for the scheduler.

dns defines the options for the DNS add-on installed in the cluster.

proxy defines the options for the proxy add-on installed in the cluster.

certificatesDir specifies where to store or look for all required certificates.

imageRepository sets the container registry to pull images from. If empty, registry.k8s.io will be used by default. In case of kubernetes version is a CI build (kubernetes version starts with ci/) gcr.io/k8s-staging-ci-images will be used as a default for control plane components and for kube-proxy, while registry.k8s.io will be used for all the other images.

featureGates contains the feature gates enabled by the user.

The cluster name.

encryptionAlgorithm holds the type of asymmetric encryption algorithm used for keys and certificates. Can be “RSA” (default algorithm, key size is 2048) or “ECDSA” (uses the P-256 elliptic curve).

bootstrapTokens is respected at kubeadm init time and describes a set of Bootstrap Tokens to create. This information IS NOT uploaded to the kubeadm cluster configmap, partly because of its sensitive nature

dryRun tells if the dry run mode is enabled, don’t apply any change in dry run mode, just out put what would be done.

nodeRegistration holds fields that relate to registering the new control-plane node to the cluster.

localAPIEndpoint represents the endpoint of the API server instance that’s deployed on this control plane node. In HA setups, this differs from ClusterConfiguration.controlPlaneEndpoint in the sense that controlPlaneEndpoint is the global endpoint for the cluster, which then loadbalances the requests to each individual API server. This configuration object lets you customize what IP/DNS name and port the local API server advertises it’s accessible on. By default, kubeadm tries to auto-detect the IP of the default interface and use that, but in case that process fails you may set the desired value here.

certificateKey sets the key with which certificates and keys are encrypted prior to being uploaded in a Secret in the cluster during the uploadcerts init phase. The certificate key is a hex encoded string that is an AES key of size 32 bytes.

skipPhases is a list of phases to skip during command execution. The list of phases can be obtained with the kubeadm init —help command. The flag —skip-phases takes precedence over this field.

patches contains options related to applying patches to components deployed by kubeadm during kubeadm init.

dryRun tells if the dry run mode is enabled, don’t apply any change if it is set, just output what would be done.

nodeRegistration holds fields that relate to registering the new control-plane node to the cluster

caCertPath is the path to the SSL certificate authority used to secure comunications between node and control-plane. Defaults to “/etc/kubernetes/pki/ca.crt”.

discovery specifies the options for the kubelet to use during the TLS bootstrap process.

controlPlane defines the additional control plane instance to be deployed on the joining node. If nil, no additional control plane instance will be deployed.

skipPhases is a list of phases to skip during command execution. The list of phases can be obtained with the kubeadm join —help command. The flag —skip-phases takes precedence over this field.

patches contains options related to applying patches to components deployed by kubeadm during kubeadm join.

cleanupTmpDir specifies whether the “/etc/kubernetes/tmp” directory should be cleaned during the reset process.

certificatesDir specifies the directory where the certificates are stored. If specified, it will be cleaned during the reset process.

criSocket is used to retrieve container runtime inforomation and used for the removal of the containers. If criSocket is not specified by flag or config file, kubeadm will try to detect one valid CRI socket instead.

dryRun tells if the dry run mode is enabled, don’t apply any change if it is set and just output what would be done.

The force flag instructs kubeadm to reset the node without prompting for confirmation.

ignorePreflightErrors provides a list of pre-flight errors to be ignored during the reset process, e.g. IsPrivilegedUser,Swap. Value all ignores errors from all checks.

skipPhases is a list of phases to skip during command execution. The list of phases can be obtained with the kubeadm reset phase —help command.

dvertiseAddress sets the IP address for the API server to advertise.

bindPort sets the secure port for the API Server to bind to. Defaults to 6443.

certSANs sets extra Subject Alternative Names (SANs) for the API Server signing certificate.

timeoutForControlPlane controls the timeout that we use for API server to appear.

The name of the argument.

The value of the argument.

token is a token used to validate cluster information fetched from the control-plane.

apiServerEndpoint is an IP or domain name to the API server from which information will be fetched.

caCertHashes specifies a set of public key pins to verify when token-based discovery is used. The root CA found during discovery must match one of these values. Specifying an empty set disables root CA pinning, which can be unsafe. Each hash is specified as <type>:<value>, where the only currently supported type is “sha256”. This is a hex-encoded SHA-256 hash of the Subject Public Key Info (SPKI) object in DER-encoded ASN.1. These hashes can be // calculated using, for example, OpenSSL.

unsafeSkipCAVerification allows token-based discovery without CA verification via caCertHashes. This can weaken the security of kubeadm since other nodes can impersonate the control-plane.

extraArgs is an extra set of flags to pass to the control plane component. An argument name in this list is the flag name as it appears on the command line except without leading dash(es). Extra arguments will override existing default arguments. Duplicate extra arguments are allowed.

extraVolumes is an extra set of host volumes, mounted to the control plane component.

extraEnvs is an extra set of environment variables to pass to the control plane component. Environment variables passed using extraEnvs will override any existing environment variables, or *_proxy environment variables that kubeadm adds by default.

imageMeta allows to customize the image used for the DNS addon.

disabled specifies whether to disable this addon in the cluster.

bootstrapToken is used to set the options for bootstrap token based discovery. bootstrapToken and file are mutually exclusive.

file is used to specify a file or URL to a kubeconfig file from which to load cluster information. bootstrapToken and file are mutually exclusive.

tlsBootstrapToken is a token used for TLS bootstrapping. If bootstrapToken is set, this field is defaulted to bootstrapToken.token, but can be overridden. If file is set, this field must be set in case the KubeConfigFile does not contain any other authentication information.

timeout modifies the discovery timeout.

local provides configuration knobs for configuring the local etcd instance. local and external are mutually exclusive.

external describes how to connect to an external etcd cluster. local and external are mutually exclusive.

endpoints contains the list of etcd members.

caFile is an SSL Certificate Authority (CA) file used to secure etcd communication. Required if using a TLS connection.

certFile is an SSL certification file used to secure etcd communication. Required if using a TLS connection.

keyFile is an SSL key file used to secure etcd communication. Required if using a TLS connection.

kubeConfigPath is used to specify the actual file path or URL to the kubeconfig file from which to load cluster information.

name is the name of the volume inside the Pod template.

hostPath is the path in the host that will be mounted inside the Pod.

mountPath is the path inside the Pod where hostPath will be mounted.

readOnly controls write access to the volume.

pathType is the type of the hostPath.

imageRepository sets the container registry to pull images from. if not set, the imageRepository defined in ClusterConfiguration will be used instead.

imageTag allows to specify a tag for the image. In case this value is set, kubeadm does not change automatically the version of the above components during upgrades.

localAPIEndpoint represents the endpoint of the API server instance to be deployed on this node.

certificateKey is the key that is used for decryption of certificates after they are downloaded from the Secret upon joining a new control plane node. The corresponding encryption key is in the InitConfiguration. The certificate key is a hex encoded string that is an AES key of size 32 bytes.

ImageMeta allows to customize the container used for etcd

dataDir is the directory etcd will place its data. Defaults to “/var/lib/etcd”.

extraArgs are extra arguments provided to the etcd binary when run inside a static Pod. An argument name in this list is the flag name as it appears on the command line except without leading dash(es). Extra arguments will override existing default arguments. Duplicate extra arguments are allowed.

extraEnvs is an extra set of environment variables to pass to the control plane component. Environment variables passed using extraEnvs will override any existing environment variables, or *_proxy environment variables that kubeadm adds by default.

serverCertSANs sets extra Subject Alternative Names (SANs) for the etcd server signing certificate.

peerCertSANs sets extra Subject Alternative Names (SANs) for the etcd peer signing certificate.

serviceSubnet is the subnet used by Kubernetes Services. Defaults to “10.96.0.0/12”.

podSubnet is the subnet used by Pods.

dnsDomain is the dns domain used by Kubernetes Services. Defaults to “cluster.local”.

name is the .Metadata.Name field of the Node API object that will be created in this kubeadm init or kubeadm join operation. This field is also used in the CommonName field of the kubelet’s client certificate to the API server. Defaults to the hostname of the node if not provided.

criSocket is used to retrieve container runtime info. This information will be annotated to the Node API object, for later re-use.

taints specifies the taints the Node API object should be registered with. If this field is unset, i.e. nil, it will be defaulted with a control-plane taint for control-plane nodes. If you don’t want to taint your control-plane node, set this field to an empty list, i.e. taints: [] in the YAML file. This field is solely used for Node registration.

kubeletExtraArgs passes through extra arguments to the kubelet. The arguments here are passed to the kubelet command line via the environment file kubeadm writes at runtime for the kubelet to source. This overrides the generic base-level configuration in the kubelet-config ConfigMap. Flags have higher priority when parsing. These values are local and specific to the node kubeadm is executing on. An argument name in this list is the flag name as it appears on the command line except without leading dash(es). Extra arguments will override existing default arguments. Duplicate extra arguments are allowed.

ignorePreflightErrors provides a slice of pre-flight errors to be ignored when the current node is registered, e.g. ‘IsPrivilegedUser,Swap’. Value ‘all’ ignores errors from all checks.

imagePullPolicy specifies the policy for image pulling during kubeadm init and join operations. The value of this field must be one of “Always”, “IfNotPresent” or “Never”. If this field is unset kubeadm will default it to “IfNotPresent”, or pull the required images if not present on the host.

directory is a path to a directory that contains files named “target[suffix][+patchtype].extension”. For example, “kube-apiserver0+merge.yaml” or just “etcd.json”. “target” can be one of “kube-apiserver”, “kube-controller-manager”, “kube-scheduler”, “etcd”, “kubeletconfiguration”. “patchtype” can be one of “strategic”, “merge” or “json” and they match the patch formats supported by kubectl. The default “patchtype” is “strategic”. “extension” must be either “json” or “yaml”. “suffix” is an optional string that can be used to determine which patches are applied first alpha-numerically.

disabled specifies whether to disable this addon in the cluster.