This example domain contains three nodes. Each node has both the service and compute roles enabled.
All nodes run the Service Manager. Node 1 is the master gateway node and runs two application services. Node 2 is a back-up gateway node and runs one application service. Node 3 is a worker node and runs one application service. If Node 1 becomes unavailable, Node 2 is elected as the new master gateway node. The Service Manager on Node 2 then performs all domain functions. When Node 1 restarts, it becomes a back-up gateway node and the Service Manager performs limited domain functions.
The following image shows a domain with two gateway nodes and one worker node: