No, you can’t install server and agent on the same node. The server also runs the agent components, as shown here: https://k3s.io/#:~:text=how%20it%20works If you’re interested in HA, you would usually have 3 or 5 servers, and then some number of agents, assuming you don’t want your workload to also run on the server and have tainted them to prevent that from occurring. If you are OK with the workload on the servers, then you don’t need any agents.