Kube Login

Tested Versions#

• Authelia
  • v4.39.5
• Kube Login
  • v1.33.0

Before You Begin#

Common Notes#

1. The OpenID Connect 1.0 client_id parameter:
   1. This must be a unique value for every client.
   2. The value used in this guide is merely for readability and demonstration purposes and you should not use this value in production and should instead utilize the How do I generate a client identifier or client secret? FAQ. We recommend 64 random characters but you can use any arbitrary value that meets the other criteria.
   3. This must only contain RFC3986 Unreserved Characters.
   4. This must be no more than 100 characters in length.
2. The OpenID Connect 1.0 client_secret parameter:
   1. The value used in this guide is merely for demonstration purposes and you should absolutely not use this value in production and should instead utilize the How do I generate a client identifier or client secret? FAQ.
   2. This string may be stored as plaintext in the Authelia configuration but this behaviour is deprecated and is not guaranteed to be supported in the future. See the Plaintext guide for more information.
   3. When the secret is stored in hashed form in the Authelia configuration (heavily recommended), the cost of hashing can, if too great, cause timeouts for clients. See the Tuning the work factors guide for more information.
3. The configuration example for Authelia:
   1. Only contains an example configuration for the client registration and you MUST also configure the required elements from the OpenID Connect 1.0 Provider Configuration guide.
   2. Only contains a small portion of all of the available options for a registered client and users may wish to configure portions that are not part of this guide or configure them differently, as such it’s important to both familiarize yourself with the other options available and the effect of each of the options configured in this section by looking at the OpenID Connect 1.0 Clients Configuration guide.

Assumptions#

This example makes the following assumptions:

• Authelia Root URL: https://auth.example.com/
• Client ID: kube_login
• Client Secret: insecure_secret

Some of the values presented in this guide can automatically be replaced with documentation variables.

Set Documentation Variables

Configuration#

Authelia#

The following YAML configuration is an example Authelia client configuration for use with Kube Login which will operate with the application example:

identity_providers:
  oidc:
    ## The other portions of the mandatory OpenID Connect 1.0 configuration go here.
    ## See: https://www.authelia.com/c/oidc
    clients:
      - client_id: "kube_login"
        client_name: "Kubernetes Cluster Access"
        client_secret: 'insecure_secret'
        public: false
        authorization_policy: "two_factor"
        redirect_uris:
          - "http://localhost:8000"
          - "http://localhost:18000"
        scopes:
          - "openid"
          - "groups"
          - "email"
          - "profile"
        userinfo_signed_response_alg: "none"
        token_endpoint_auth_method: "client_secret_basic"

Kubernetes API Server Configuration#

Configure your Kubernetes API server to trust Authelia as an OIDC provider by adding these arguments:

--oidc-issuer-url=https://auth.example.com
--oidc-client-id=kube_login
--oidc-groups-claim=groups

See the Kubernetes Flags Documentation for more information on these options.

How to Apply These Arguments#

The method for configuring API server arguments varies by Kubernetes distribution. Consult the Kubernetes OIDC Authentication documentation for detailed instructions on applying these arguments to your specific setup.

Common distributions:

• K3s: Add to /etc/rancher/k3s/config.yaml under kube-apiserver-arg:
• kubeadm: Edit /etc/kubernetes/manifests/kube-apiserver.yaml
• Managed services: Use provider-specific tools (AWS CLI, gcloud, az cli)

RBAC Configuration#

After configuring OIDC authentication, create RBAC rules to authorize your users. Choose the approach that fits your needs:

Group-Based Access#

# Admins group - full cluster access
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: authelia-admins
subjects:
- kind: Group
  name: admins
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: ClusterRole
  name: cluster-admin # NOTE this role gives COMPLETE access to the kubernetes api
  apiGroup: rbac.authorization.k8s.io

---
# Developers group - namespace-specific access
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: authelia-developers
  namespace: development
subjects:
- kind: Group
  name: developers
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: ClusterRole
  name: edit
  apiGroup: rbac.authorization.k8s.io

Per User Access#

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: authelia-user-admin
subjects:
- kind: User
  name: "https://auth.example.com#your-user-sub-claim"
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: ClusterRole
  name: cluster-admin # NOTE this role gives COMPLETE access to the kubernetes api
  apiGroup: rbac.authorization.k8s.io

Note: You can obtain all user sub identifiers using the following command: authelia storage user identifiers export

Client Configuration (kubectl + kubelogin)#

Install Required Tools#

1. Install kubectl (if not already installed) - Installation Guide
2. Install krew (kubectl plugin manager): - Installation Guide
3. Install kubelogin - kubectl krew install oidc-login

Configure kubeconfig#

Use kubectl commands to set up the OIDC user on your local machine:

kubectl config set-credentials authelia \
  --exec-api-version=client.authentication.k8s.io/v1beta1 \
  --exec-command=kubectl \
  --exec-arg=oidc-login \
  --exec-arg=get-token \
  --exec-arg=--oidc-issuer-url=https://auth.example.com \
  --exec-arg=--oidc-client-id=kube_login \
  --exec-arg=--oidc-client-secret=insecure_secret \
  --exec-arg=--oidc-extra-scope=groups

Setup Context#

Create and use a context with the OIDC user:

# Create context (replace 'your-cluster' with your actual cluster name)
kubectl config set-context authelia \
  --cluster=your-cluster \
  --user=authelia

# Switch to the new context
kubectl config use-context authelia

Testing the Configuration#

# This should start the OIDC authentication flow in your browser.
kubectl get nodes

See Also#

• Kube Login Usage Documentation