Kubernetes auth method (API)

warning

Note: This engine can use external X.509 certificates as part of TLS or signature validation. Verifying signatures against X.509 certificates that use SHA-1 is deprecated and is no longer usable without a workaround. See the deprecation FAQ for more information.

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

This documentation assumes the Kubernetes method is mounted at the /auth/kubernetes path in OpenBao. 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.

Method	Path
POST	/auth/kubernetes/config

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: "") - PEM encoded CA cert for use by the TLS client used to talk with the Kubernetes API. NOTE: Every line must end with a newline: \n If not set, the local CA cert will be used if running in a Kubernetes pod.
• token_reviewer_jwt (string: "") - A service account JWT used 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.

Deprecated parameters

info

The following fields have been deprecated and will be removed in a future release:

• 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 OpenBao 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). This behavior may be disabled by setting disable_local_ca_jwt to true.

When OpenBao is running in a non-Kubernetes environment, either kubernetes_ca_cert or pem_keys must be set by the user.

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.

Method	Path
GET	/auth/kubernetes/config

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
  }
}

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.

Method	Path
POST	/auth/kubernetes/role/:name

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: <required>) - List of namespaces allowed to access this role. If set to "*" all namespaces are allowed.
• 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, serviceaccount_name When serviceaccount_uid is specified, the machine generated UID from the service account will be used as the identity alias name. When serviceaccount_name is specified, the service account's namespace and name will be used as the identity alias name e.g openbao/openbao-auth. While it is strongly advised that you use serviceaccount_uid, you may also use serviceaccount_name in cases where you want to set the alias ahead of time, and the risks are mitigated or otherwise acceptable given your use case. It is very important to limit who is able to delete/create service accounts within a given cluster. 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_strictly_bind_ip (bool: false) - If set, the token will be restricted to the source IP address making the initial login request. This conflicts with token_bound_cidrs.
• 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.

Sample payload

{
  "bound_service_account_names": "openbao-auth",
  "bound_service_account_namespaces": "default",
  "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.

Method	Path
GET	/auth/kubernetes/role/:name

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": "openbao-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.

Method	Path
LIST	/auth/kubernetes/role
GET	/auth/kubernetes/role?list=true

Parameters

• after (string: "") - Optional entry to begin listing after for pagination; not required to exist.

• limit (int: 0) - Optional number of entries to return; defaults to all entries.

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.

Method	Path
DELETE	/auth/kubernetes/role/: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.

Method	Path
POST	/auth/kubernetes/login

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": "openbao-auth",
      "service_account_namespace": "default",
      "service_account_secret_name": "openbao-auth-token-pd21c",
      "service_account_uid": "aa9aa8ff-98d0-11e7-9bb7-0800276d99bf"
    },
    "lease_duration": 2764800,
    "renewable": true
  }
}