Kubernetes auth method (API)

This is the API documentation for the Vault Kubernetes auth method plugin. To learn more about the usage and operation, see the Vault Kubernetes auth method.

This documentation assumes the Kubernetes method is mounted at the /auth/kubernetes path in Vault. Since it is possible to enable auth methods at any location, please update your API calls accordingly.

Configure method

The Kubernetes auth method validates service account JWTs and verifies their existence with the Kubernetes TokenReview API. This endpoint configures the public key used to validate the JWT signature and the necessary information to access the Kubernetes API.

Parameters

• kubernetes_host (string: <required>) - Host must be a host string, a host:port pair, or a URL to the base of the Kubernetes API server.
• kubernetes_ca_cert (string: "") - Optional PEM encoded CA cert that the TLS client can use to talk with the Kubernetes API. Every line must end with a newline \n. If kubernetes_ca_cert is unset, the TLS client uses the local CA cert if Vault is running in a Kubernetes pod. If kubernetes_ca_cert is unset and disable_local_ca_jwt set to true, the TLS client uses the system's trusted CA certificate pool.
• token_reviewer_jwt (string: "") - A service account JWT (or other token) used as a bearer token to access the TokenReview API to validate other JWTs during login. If not set, the local service account token is used if running in a Kubernetes pod, otherwise the JWT submitted in the login payload will be used to access the Kubernetes TokenReview API.
• pem_keys (array: []) - Optional list of PEM-formatted public keys or certificates used to verify the signatures of Kubernetes service account JWTs. If a certificate is given, its public key will be extracted. Not every installation of Kubernetes exposes these keys.
• disable_local_ca_jwt (bool: false) - Disable defaulting to the local CA cert and service account JWT when running in a Kubernetes pod.
• use_annotations_as_alias_metadata (bool: false) - Use annotations from the client token's associated service account as alias metadata for the Vault entity. Only annotations with the vault.hashicorp.com/alias-metadata- key prefix are targeted as alias metadata and your annotations must be 512 characters or less due to the Vault alias metadata value limit. For example, if you configure the annotation vault.hashicorp.com/alias-metadata-foo, Vault saves the string "foo" along with the annotation value to the alias metadata. To save alias metadata, Vault must have permission to read service accounts from the Kubernetes API.

Deprecated parameters

• disable_iss_validation (bool: true) Deprecated Disable JWT issuer validation. Allows to skip ISS validation.

• issuer (string: "") Deprecated Optional JWT issuer. If no issuer is specified, then this plugin will use kubernetes/serviceaccount as the default issuer. See these instructions for looking up the issuer for a given Kubernetes cluster.

Caveats

If Vault is running in a Kubernetes Pod, the kubernetes_ca_cert and token_reviewer_jwt parameters will automatically default to the local CA cert (/var/run/secrets/kubernetes.io/serviceaccount/ca.crt) and local service account JWT (/var/run/secrets/kubernetes.io/serviceaccount/token).

If you override the default local CA cert behavior by setting disable_local_ca_jwt to true, the plugin's TLS client will automatically default to using the system's trust store for TLS certificate verification.

Sample payload

{
  "kubernetes_host": "https://192.168.99.100:8443",
  "kubernetes_ca_cert": "-----BEGIN CERTIFICATE-----\n.....\n-----END CERTIFICATE-----",
  "pem_keys": "-----BEGIN CERTIFICATE-----\n.....\n-----END CERTIFICATE-----"
}

Sample request

$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
    --data @payload.json \
    http://127.0.0.1:8200/v1/auth/kubernetes/config

Read config

Returns the previously configured config, excluding credentials.

Sample request

$ curl \
    --header "X-Vault-Token: ..." \
    http://127.0.0.1:8200/v1/auth/kubernetes/config

Sample response

{
  "data":{
    "kubernetes_host": "https://192.168.99.100:8443",
    "kubernetes_ca_cert": "-----BEGIN CERTIFICATE-----.....-----END CERTIFICATE-----",
    "pem_keys": ["-----BEGIN CERTIFICATE-----.....", .....],
    "disable_local_ca_jwt": false,
    "token_reviewer_jwt_set": false
  }
}

Create/Update role

Registers a role in the auth method. Role types have specific entities that can perform login operations against this endpoint. Constraints specific to the role type must be set on the role. These are applied to the authenticated entities attempting to login.

Parameters

• name (string: <required>) - Name of the role.

• bound_service_account_names (array: <required>) - List of service account names able to access this role. If set to "*" all names are allowed.

• bound_service_account_namespaces (array: []) - List of namespaces allowed to access this role. If set to "*" all namespaces are allowed.

• bound_service_account_namespace_selector (string: "") - A label selector for Kubernetes namespaces allowed to access this role. Accepts either a JSON or YAML object. The value should be of type LabelSelector. Currently, label selectors with matchExpressions are not supported. To use label selectors, Vault must have permission to read namespaces on the Kubernetes cluster. If set with bound_service_account_namespaces, the conditions are ORed.

• audience (string: "") - Optional Audience claim to verify in the JWT.

• alias_name_source (string: "serviceaccount_uid") - Configures how identity aliases are generated. Valid choices are: serviceaccount_uid and serviceaccount_name.

  When you specify serviceaccount_uid, Vault uses a machine generated UID from the service account as the identity alias name. Using a service account UID is both the default and the recommended method as it the more secure option.

  When you specify serviceaccount_name, Vault uses the name and namespace from the service account as the identity alias name (e.g., vault/vault-auth). You should only use serviceaccount_name if you consider the risk acceptable or can mitigate the risk with strong controls around the creation/deletion/access of your Kubernetes service accounts and need one of the following capabilities:

  1. fine-grained control over the mapping between Kubernetes service accounts and Vault identities.
  2. a simpler process for setting entity aliases before creating Kubernetes service account creation.

  See the Create an Entity Alias document which further expands on the potential security implications mentioned above.

• token_ttl (integer: 0 or string: "") - The incremental lifetime for generated tokens. This current value of this will be referenced at renewal time.
• token_max_ttl (integer: 0 or string: "") - The maximum lifetime for generated tokens. This current value of this will be referenced at renewal time.
• token_policies (array: [] or comma-delimited string: "") - List of token policies to encode onto generated tokens. Depending on the auth method, this list may be supplemented by user/group/other values.
• policies (array: [] or comma-delimited string: "") - DEPRECATED: Please use the token_policies parameter instead. List of token policies to encode onto generated tokens. Depending on the auth method, this list may be supplemented by user/group/other values.

• token_bound_cidrs (array: [] or comma-delimited string: "") - List of CIDR blocks; if set, specifies blocks of IP addresses which can authenticate successfully, and ties the resulting token to these blocks as well.
• token_explicit_max_ttl (integer: 0 or string: "") - If set, will encode an explicit max TTL onto the token. This is a hard cap even if token_ttl and token_max_ttl would otherwise allow a renewal.
• token_no_default_policy (bool: false) - If set, the default policy will not be set on generated tokens; otherwise it will be added to the policies set in token_policies.
• token_num_uses (integer: 0) - The maximum number of times a generated token may be used (within its lifetime); 0 means unlimited. If you require the token to have the ability to create child tokens, you will need to set this value to 0.
• token_period (integer: 0 or string: "") - The maximum allowed period value when a periodic token is requested from this role.
• token_type (string: "") - The type of token that should be generated. Can be service, batch, or default to use the mount's tuned default (which unless changed will be service tokens). For token store roles, there are two additional possibilities: default-service and default-batch which specify the type to return unless the client requests a different type at generation time. For machine based authentication cases, you should use batch type tokens.

Sample Payload 1

{
  "bound_service_account_names": "vault-auth",
  "bound_service_account_namespaces": "default",
  "policies": ["dev", "prod"],
  "max_ttl": 1800000
}

Sample Payload 2

{
  "bound_service_account_names": "vault-auth",
  "bound_service_account_namespace_selector": "\"{\"matchLabels\":{\"stage\":\"dev\",\"vault-role\":\"dev-role\"}}",
  "policies": ["dev", "prod"],
  "max_ttl": 1800000
}

Sample Request

$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
    --data @payload.json \
    http://127.0.0.1:8200/v1/auth/kubernetes/role/dev-role

Read role

Returns the previously registered role configuration.

Parameters

• name (string: <required>) - Name of the role.

Sample request

$ curl \
    --header "X-Vault-Token: ..." \
    http://127.0.0.1:8200/v1/auth/kubernetes/role/dev-role

Sample response

{
  "data": {
    "bound_service_account_names": "vault-auth",
    "bound_service_account_namespaces": "default",
    "max_ttl": 1800000,
    "ttl": 0,
    "period": 0,
    "policies": ["dev", "prod"]
  }
}

List roles

Lists all the roles that are registered with the auth method.

Sample request

$ curl \
    --header "X-Vault-Token: ..." \
    --request LIST \
    http://127.0.0.1:8200/v1/auth/kubernetes/role

Sample response

{
  "data": {
    "keys": ["dev-role", "prod-role"]
  }
}

Delete role

Deletes the previously registered role.

Parameters

• role (string: <required>) - Name of the role.

Sample request

$ curl \
    --header "X-Vault-Token: ..." \
    --request DELETE \
    http://127.0.0.1:8200/v1/auth/kubernetes/role/dev-role

Login

Fetch a token. This endpoint takes a signed JSON Web Token (JWT) and a role name for some entity. It verifies the JWT signature to authenticate that entity and then authorizes the entity for the given role.

Parameters

• role (string: <required>) - Name of the role against which the login is being attempted.
• jwt (string: <required>) - Signed JSON Web Token (JWT) for authenticating a service account.

Sample payload

{
  "role": "dev-role",
  "jwt": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

Sample request

$ curl \
    --request POST \
    --data @payload.json \
    http://127.0.0.1:8200/v1/auth/kubernetes/login

Sample response

{
  "auth": {
    "client_token": "62b858f9-529c-6b26-e0b8-0457b6aacdb4",
    "accessor": "afa306d0-be3d-c8d2-b0d7-2676e1c0d9b4",
    "policies": ["default"],
    "metadata": {
      "role": "test",
      "service_account_name": "vault-auth",
      "service_account_namespace": "default",
      "service_account_secret_name": "vault-auth-token-pd21c",
      "service_account_uid": "aa9aa8ff-98d0-11e7-9bb7-0800276d99bf"
    },
    "lease_duration": 2764800,
    "renewable": true
  }
}