Oracle Process Manager and Notification server (OPMN) enables you to monitor and control the Essbase Agent process. You add Essbase Agent information to the opmn.xml file to enable Oracle Process Manager and Notification Server to start, stop, and restart the agent using the OPMN command line interface. OPMN can automatically restart the Essbase Agent when it become unresponsive, terminates unexpectedly, or becomes unreachable as determined by ping and notification operations. OPMN is installed in EPM_HOME.
Figure 148, Essbase Integration with OPMN shows how Essbase integrates with OPMN.
Additionally, you can use the failover functionality available in OPMN to provide high availability of Essbase clusters (see Understanding Essbase Failover Clusters).
Oracle Process Manager Modules (PM Modules) communicate with the Essbase Agent for process administration and health monitoring. As a managed component, the Essbase Agent and OPMN communicate using Oracle Notification Server (ONS), which is the transport mechanism for notifications between components.
When you start Essbase using the OPMN command line interface (see Starting and Stopping Essbase Using OPMN), OPMN spawns the agent process and sets the status to initialized (a message is logged in the opmn.log file). Whether this state transitions to alive depends on whether OPMN receives a response (a reverse ping) from the agent, which implies that the agent is active.
After Essbase is up and running, OPMN periodically sends a TCP-based forward ping to the agent. If a ping attempt fails, OPMN retries up to three times to contact the agent. If all ping attempts fail, OPMN stops the agent. OPMN attempts to restart the agent for these scenarios:
restart-on-death (in opmn.xml) is set to TRUE.
In a production environment, restart-on-death should always be set to TRUE. Oracle recommends trying to restart a process on the local node first, before attempting failover. When restart-on-death is set to TRUE, OPMN first attempts to restart Essbase on the local node for the number of restarts that are configured in opmn.xml (the first start and the number of restarts). If all restart attempts fail, then failover to the standby node occurs.
In development and test environments, you can set restart-on-death to FALSE to test failover.
In non-failover mode, which is the default mode, the default setting for restart-on-death is FALSE.
Failover mode is on, which supersedes the restart-on-death value. If restart-on-death is FALSE and failover mode is on, OPMN may bring up Essbase on the active or passive node.
When you stop Essbase using the OPMN command line interface, OPMN shuts down the agent, thereby releasing all resources held by the agent. Essbase Servers shut down when they detect that the parent agent process has shut down.