A node is the logical representation of a machine in a domain. One node in the domain acts as a gateway to receive service requests from clients and route them to the appropriate service and node. Services and processes run on nodes in a domain.
A Primary Node is configured as the default node to run a Service Process. By default, the Service Manager starts the service process on the primary node and uses a backup node if the primary node fails. Any node that is configured to run a service process, but is not configured as a primary node is the Backup Node.
Any node that is configured to run a service process, but is not configured as a primary node is the Backup Node.
A gateway node is any node that you configure to serve as a gateway for the domain. A gateway node can run application services and perform computations, and it can serve as a master gateway node. One gateway node acts as the master gateway at any given time. The master gateway node is the entry point to the domain.
The Service Manager on the master gateway node performs all domain functions on the master gateway node. The Service Managers running on other gateway nodes perform limited domain functions on those nodes.
You can configure more than one node to serve as a gateway. If the master gateway node becomes unavailable, the Service Managers on other gateway nodes elect another master gateway node. If you configure only one node to serve as the gateway and the node becomes unavailable, the domain cannot accept service requests.
A worker node is any node that you do not configure to serve as a gateway for the domain. A worker node can run application services and perform computations, but it cannot serve as a gateway. The Service Manager performs limited domain functions on a worker node.