Leader

When you start your Docker containers, the first one will become the Leader and is responsible for running background tasks such as Alerts and Scheduled Flows.

If the Leader fails then one of the other servers will take over as the Leader.

You should be aware that in a Level 1 cluster, if the server that fails is running the databases and Redis, then this will bring the system down. If high availability is important then you should use a Level 2 cluster.