Showing Service Dependencies

Dependency relationships govern service instance state transitions. See Service Dependencies for a high-level description of dependencies. See Chapter 5, Using SMF to Control Your Application for detailed descriptions and how to specify different kinds of dependencies.

In the following figure, the svc1:default, svc2:default, and svc3:default service instances do not require any other services or any files or other resources to start. These instances can start in parallel, execute their start methods, and move to the online state without waiting on any other resources. The svc4:default instance cannot execute its start method until the svc2:default instance is online. The svc5:inst1 instance needs both svc2:default resources and svc4:default resources. The dependency that svc5:inst1 has on svc4:default is an optional dependency and is satisfied if svc4:default is in one of the following states: enabled and online, disabled, or not present. The svc5:inst1 instance must wait until svc2:default is online, and if svc4:default is present and enabled, svc5:inst1 must also wait until svc4:default is online. If svc4:default is present and disabled or is not present, svc5:inst1 does not need to wait for svc4:default.

Figure 2-1  Service Dependency Relationships