Probe_command Property

This property specifies the probe command that periodically checks the health of a given application. This command must be a UNIX command with arguments that can be passed directly to a shell to probe the application. The probe command returns with an exit status of 0 if the application is running correctly.

The exit status of the probe command is used to determine the severity of the application's failure. This exit status, called the probe status, must be an integer between 0 (for success) and 100 (for complete failure). The probe status can also be a special value of 201, which causes the application to immediately fail over unless Failover_enabled is set to FALSE. The GDS probing algorithm uses the probe status to determine whether to restart the application locally or fail it over. See the scds_fm_action(3HA) man page for more information. If the exit status is 201, the application is immediately failed over.

If the probe command is omitted, the GDS provides its own simple probe. This probe connects to the application on the set of IP addresses that is derived from the Network_resources_used property or from the output of the scds_get_netaddr_list() function. See the scds_get_netaddr_list(3HA) man page for more information. If the connect succeeds, the connect disconnects immediately. If both the connect and disconnect succeed, the application is deemed to be running well.

The probe that is provided with the GDS is only intended to be a simple substitute for the fully functioning application-specific probe.