Join a worker node#

Joining worker nodes to your control plane is similar to the process of joining worker nodes with k0s. You need to obtain a join token that establishes mutual trust between the worker node and control plane, allowing the node to join the cluster as worker.

To join a worker node to the cluster:

Obtain a join token:

Create a JoinTokenRequest resource to generate a join token for the worker node. For example:

apiVersion: k0smotron.io/v1beta1
kind: JoinTokenRequest
metadata:
  name: my-token
  namespace: default
spec:
  clusterRef:
    name: my-cluster
    namespace: default
  expiry: 1h

Tip

The expiry field defines the expiration time of the token. Refer to API reference: JoinTokenRequest.spec for the configuration details.

k0smotron processes the JoinTokenRequest resource and creates a Secret resource:

apiVersion: v1
kind: Secret
metadata:
  name: my-token
  namespace: default
  labels:
    k0smotron.io/cluster: my-cluster.default
    k0smotron.io/role: worker
    k0smotron.io/token-request: my-token
type: Opaque
data:
  token: <base64-encoded-token>

The token field contains the base64-encoded token that you can use to join a worker node to the cluster.

Retrieve the decoded join token from the generated Secret:

kubectl get secret my-token -o jsonpath='{.data.token}' | base64 -d

Install k0s on the worker node:
1. Ensure that the k0s binary is installed on the worker node:
```
curl -sSLf https://get.k0s.sh | sudo sh
```
2. Verify that the k0s version in the worker node matches the k0s version installed on the control plane. If needed, you can adjust the k0s version using the K0S_VERSION environment variable.

Join the worker node specifying the join token created earlier:

sudo k0s install worker --token-file /path/to/token/file
sudo k0s start

Delete the JoinTokenRequest resource to invalidate the issued token:
```
kubectl delete jointokenrequest my-token
```

Note

API reference: JoinTokenRequest.spec