161 lines
6.4 KiB
Plaintext
161 lines
6.4 KiB
Plaintext
---
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layout: docs
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page_title: Kubernetes Auth Method
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description: >-
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The Kubernetes auth method type allows for a Kubernetes service account token
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to be used to authenticate to Consul. This method of authentication makes it
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easy to introduce a Consul token into a Kubernetes pod.
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---
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# Kubernetes Auth Method
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-> **1.5.0+:** This feature is available in Consul versions 1.5.0 and newer.
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The `kubernetes` auth method type allows for a Kubernetes service account token
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to be used to authenticate to Consul. This method of authentication makes it
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easy to introduce a Consul token into a Kubernetes pod.
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This page assumes general knowledge of [Kubernetes](https://kubernetes.io/) and
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the concepts described in the main [auth method
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documentation](/docs/security/acl/auth-methods).
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## Config Parameters
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The following auth method [`Config`](/api/acl/auth-methods#config)
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parameters are required to properly configure an auth method of type
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`kubernetes`:
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- `Host` `(string: <required>)` - Must be a host string, a host:port pair, or a
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URL to the base of the Kubernetes API server.
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- `CACert` `(string: <required>)` - PEM encoded CA cert for use by the TLS
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client used to talk with the Kubernetes API. NOTE: Every line must end with a
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newline (`\n`). If not set, system certificates are used.
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- `ServiceAccountJWT` `(string: <required>)` - A Service Account Token
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([JWT](https://jwt.io/ 'JSON Web Token')) used by the Consul leader to
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validate application JWTs during login.
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- `MapNamespaces` `(bool: <false>)` <EnterpriseAlert inline /> -
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**Deprecated in Consul 1.8.0 in favor of [namespace rules](/api/acl/auth-methods#namespacerules).**
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Indicates whether the auth method should attempt to map the Kubernetes namespace to a Consul
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namespace instead of creating tokens in the auth methods own namespace. Note
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that mapping namespaces requires the auth method to reside within the
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`default` namespace.
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Deprecated in Consul 1.8.0 in favor of [namespace rules](/api/acl/auth-methods#namespacerules).
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- `ConsulNamespacePrefix` `(string: <optional>)` <EnterpriseAlert inline /> -
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**Deprecated in Consul 1.8.0 in favor of [namespace rules](/api/acl/auth-methods#namespacerules).**
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When `MapNamespaces` is enabled, this value will be prefixed to the Kubernetes
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namespace to determine the Consul namespace to create the new token within.
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Deprecated in Consul 1.8.0 in favor of [namespace rules](/api/acl/auth-methods#namespacerules).
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- `ConsulNamespaceOverrides` `(map: <string:string>)` <EnterpriseAlert inline /> -
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**Deprecated in Consul 1.8.0 in favor of [namespace rules](/api/acl/auth-methods#namespacerules).**
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This field is a mapping of Kubernetes namespace names to Consul namespace
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names. If a Kubernetes namespace is present within this map, the value will
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be used without adding the `ConsulNamespacePrefix`. If the value in the map
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is `""` then the auth methods namespace will be used instead of attempting
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to determine an alternate namespace.
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Deprecated in Consul 1.8.0 in favor of [namespace rules](/api/acl/auth-methods#namespacerules).
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### Sample Config
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```json
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{
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...other fields...
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"Config": {
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"Host": "https://192.0.2.42:8443",
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"CACert": "-----BEGIN CERTIFICATE-----\n...-----END CERTIFICATE-----\n",
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"ServiceAccountJWT": "eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9..."
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}
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}
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```
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## RBAC
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The Kubernetes service account corresponding to the configured
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[`ServiceAccountJWT`](/docs/security/acl/auth-methods/kubernetes#serviceaccountjwt)
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needs to have access to two Kubernetes APIs:
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- [**TokenReview**](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.11/#create-tokenreview-v1-authentication-k8s-io)
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-> Kubernetes should be running with `--service-account-lookup`. This is
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defaulted to true in Kubernetes 1.7, but any versions prior should ensure
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the Kubernetes API server is started with this setting.
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- [**ServiceAccount**](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.11/#read-serviceaccount-v1-core)
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(`get`)
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The following is an example
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[RBAC](https://kubernetes.io/docs/reference/access-authn-authz/rbac/)
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configuration snippet to grant the necessary permissions to a service account
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named `consul-auth-method-example`:
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```yaml
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---
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kind: ClusterRoleBinding
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apiVersion: rbac.authorization.k8s.io/v1
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metadata:
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name: review-tokens
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namespace: default
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subjects:
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- kind: ServiceAccount
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name: consul-auth-method-example
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namespace: default
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roleRef:
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kind: ClusterRole
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name: system:auth-delegator
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apiGroup: rbac.authorization.k8s.io
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---
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kind: ClusterRole
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apiVersion: rbac.authorization.k8s.io/v1
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metadata:
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name: service-account-getter
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namespace: default
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rules:
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- apiGroups: ['']
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resources: ['serviceaccounts']
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verbs: ['get']
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---
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kind: ClusterRoleBinding
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apiVersion: rbac.authorization.k8s.io/v1
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metadata:
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name: get-service-accounts
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namespace: default
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subjects:
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- kind: ServiceAccount
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name: consul-auth-method-example
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namespace: default
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roleRef:
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kind: ClusterRole
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name: service-account-getter
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apiGroup: rbac.authorization.k8s.io
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```
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## Kubernetes Authentication Details
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Initially the
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[`ServiceAccountJWT`](/docs/security/acl/auth-methods/kubernetes#serviceaccountjwt)
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given to the Consul leader uses the TokenReview API to validate the provided
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JWT. The trusted attributes of `serviceaccount.namespace`,
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`serviceaccount.name`, and `serviceaccount.uid` are populated directly from the
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Service Account metadata.
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The Consul leader makes an additional query, this time to the ServiceAccount
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API to check for the existence of an annotation of
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`consul.hashicorp.com/service-name` on the ServiceAccount object. If one is
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found its value will override the trusted attribute of `serviceaccount.name`
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for the purposes of evaluating any binding rules.
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## Trusted Identity Attributes
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The authentication step returns the following trusted identity attributes for
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use in binding rule selectors and bind name interpolation.
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| Attributes | Supported Selector Operations | Can be Interpolated |
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| -------------------------- | -------------------------------------------------- | ------------------- |
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| `serviceaccount.namespace` | Equal, Not Equal, In, Not In, Matches, Not Matches | yes |
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| `serviceaccount.name` | Equal, Not Equal, In, Not In, Matches, Not Matches | yes |
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| `serviceaccount.uid` | Equal, Not Equal, In, Not In, Matches, Not Matches | yes |
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