Add Worker Nodes to the Cluster

The Kubernetes cluster might run out of resources when handling large workloads. In these cases, adding an extra node to the cluster can help manage the increased workloads.

Add a Worker Node

Do not add a worker node during the cluster upgrade. However, you can add the worker node after the upgrade is successful.

1. Run the following command on the cluster:

   appdctl cluster add-node

   CODE
   This command generates a command to add the worker node to the cluster.
   The following is a sample output:
   

   Sample Output

   Enter the following command on the node as master to join the cluster:
   appdctl cluster join 10.X.X.X:25000/11c4d3d1234288c8d7135ce470aeb9e8/b3f373551c9b
   
   Enter the following command on the node as worker to join the cluster:
   appdctl cluster join 10.X.X.X:25000/11c4d3d1234288c8d7135ce470aeb9e8/b3f373551c9b --worker

   CODE
2. Run the command that has the --worker flag in the node that you want to join to the cluster.
   For example:
   

   appdctl cluster join 10.X.X.X:25000/11c4d3d1234288c8d7135ce470aeb9e8/b3f373551c9b --worker

   CODE
3. Verify whether the cluster includes the worker node:
   

   appdctl show cluster
   microk8s status

   CODE

   Sample Output

    NODE           | ROLE  | RUNNING
   ----------------+-------+---------
    10.0.0.1:19001 | voter | true   
    10.0.0.2:19001 | voter | true   
    10.0.0.3:19001 | voter | true
    10.0.0.4:19001 | voter | true 

   CODE

After you add a node to the cluster, restart the cluster for the node to take effect.

Delete the Worker Nodes

You can delete the worker nodes if they are not required. Complete the following steps to delete the worker nodes:

1. Run the drain command on the node.
   

   kubectl drain <Node_Name> - -ignore-daemonsets --delete-emptydir-data

   CODE

   This command prevents the node from scheduling workloads.

2. Delete the node.
   

     kubectl delete node <Node_Name>

   CODE
   This command removes the worker node from the cluster.