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How to add an authorised cluster endpoint to a RKE2 cluster created by Rancher


There is a Kubernets RKE2 cluster created by Rancher v2.6 with 3 nodes on vSphere. No authorized cluster endpoint was defined. Is there a way to add an authorized cluster endpoint after cluster was created?


Solution

  • Manual steps to be taken on the control plane of each downstream cluster to enable ACE:

    1. Create a file at /var/lib/rancher/{rke2,k3s}/kube-api-authn-webhook.yaml with the following contents:
    apiVersion: v1
    kind: Config
    clusters:
    - name: Default
      cluster:
        insecure-skip-tls-verify: true
        server: http://127.0.0.1:6440/v1/authenticate
    users:
    - name: Default
      user:
        insecure-skip-tls-verify: true
    current-context: webhook
    contexts:
    - name: webhook
      context:
        user: Default
        cluster: Default
    
    
    1. Add the following to the config file (or create one if it doesn’t exist); note that the default location is /etc/rancher/{rke2,k3s}/config.yaml:
    kube-apiserver-arg:
        - authentication-token-webhook-config-file=/var/lib/rancher/{rke2,k3s}/kube-api-authn-webhook.yaml
    
    1. Run the following commands:
    sudo systemctl stop {rke2,k3s}-server
    sudo systemctl start {rke2,k3s}-server
    
    1. Finally, you must go back to the Rancher UI and edit the imported cluster there to complete the ACE enablement. Click on ⋮ > Edit Config, then click the Networking tab under Cluster Configuration. Finally, click the Enabled button for Authorized Endpoint. Once the ACE is enabled, you then have the option of entering a fully qualified domain name (FQDN) and certificate information.