A system service runs internal processes for Platform software. System services may have multiple concurrent service instances running on multiple hosts. All system services (except for derbydb) are automatically enabled by default at installation.
By default, management services that are installed with EGO include the following:
By default, system services are registered to the ManagementServices > EGOManagementServices consumer that uses the ManagementHosts resource group. You do not need to register any non-system services to consumers using the ManagementHosts resource group, although it is recommended that you do so if your service is a scheduler or controlling service instead of a regular application (management hosts are not expected to execute workload units for users, but are configured to run important services instead).
Each started system service requires one slot, assuming the system service is configured for one instance (default setting). By default, EGO allots twelve slots per management host to run system services, although only seven (or eight if derbydb is automatically enabled at installation) are actually used out-of-the-box by the installed management services listed above. For maximum performance in case of failover, you must retain seven or eight of the ten slots on each master candidate for use by the system services; the others can be used by non-system services that you might register that require a management host.
Slots assigned to run system services for consumers the ManagementServices consumer branch do not have to be on the master host (for example, any management host in the cluster can be the web server); the cluster determines where the system service instance runs at startup.
Registered system services do not require a host, only the system service instance that it runs.
A service profile is an XML file (configured through the Platform Management Console) that contains the service definition for a service; when you update a system service, you are updating the system service profile containing the system service definition. Every service, whether it is installed by default (a system service) or added by an administrator, has a service profile. The XML file lets you configure properties for the service such as :
The maximum and minimum number of service instances required by the service
A service instance description, which describes how to start a service instance for this service
Any resources required to run the service instances for this service
Any dependencies this service has (such as another service being started)