How to Join a Node into a MicroK8s Cluster as a Worker

MicroK8s provides an easy way to create lightweight Kubernetes clusters. This guide explains how to join a new node as a worker in an existing MicroK8s cluster using the --worker flag.

1. On the Control Plane (Primary Node)

Run the following command to generate a join token:

microk8s add-node

This will output something like:

From the node you wish to join to this cluster, run the following:
microk8s join 192.168.1.100:25000/bc8c3e4fa837de1d5c4e2a7b8f...

Take note of the generated command.

2. On the New Node (Worker Node)

Run the microk8s join command provided in Step 1, but append the --worker flag:

microk8s join 192.168.1.100:25000/bc8c3e4fa837de1d5c4e2a7b8f... --worker

Replace 192.168.1.100:25000/... with the actual address and token from Step 1.

Using the --worker flag ensures the node is joined as a worker, meaning it will not run control plane services.

3. Verify the Cluster

After joining, go back to the control plane and check the node status:

microk8s kubectl get nodes

You should see the new node listed as Ready with a worker role.

4. Removing a Node (Optional)

If you need to remove a node from the cluster, run this command on the control plane:

microk8s remove-node <node-name>

Additional Notes:

Ensure all nodes are running the same MicroK8s version.
If the worker node has firewall rules, allow communication on port 25000.
Nodes might take a few minutes to be fully integrated into the cluster.
The control plane nodes handle the cluster management, while worker nodes only run workloads.

Now you're ready to scale your MicroK8s cluster with dedicated worker nodes! 🚀

swagfin/how-to-join-a-node-into-microk8s-cluster.md