Lifecycle of a server farm node

You can configure heartbeat rate and timeout values to indicate possible server problems among farm members by triggering a change in status of an affected node.

When a server configured as a farm node is started, the Administration Service on that server automatically registers it as a new farm member.

When a farm member is shut down, it automatically unregisters from the farm.

A heartbeat mechanism exists to keep track of farm members that might become unresponsive, for example, because of a power outage or a server failure. In this heartbeat mechanism, MobileFirst runtimes send periodically at a given rate a heartbeat to MobileFirst administration services. If the MobileFirst administration services register that too long a time has elapsed since a farm member sent a heartbeat, then the farm member is considered to be down.

Farm members considered to be down do not serve any more requests to mobile applications.

Having one or more nodes down does not prevent the other members of the farm from:

Serving requests correctly to mobile applications
Accepting new management operations triggered through MobileFirst Operations Console

Configuring the heartbeat rate and timeout values

You can configure the heartbeat rate and timeout values by defining the following JNDI properties:

ibm.worklight.admin.farm.heartbeat
ibm.worklight.admin.farm.missed.heartbeats.timeout

For more information, see List of JNDI properties for MobileFirst Server administration

You can check the status of farm members from MobileFirst Operations Console by clicking Server Farm Nodes.

Figure 1. Checking the status of farm nodes

MobileFirst Operations Console with the button for selecting the list of server farm nodes.

Clicking Server Farm Nodes enables you to access the list of registered farm members and their status.

Figure 2. List of server farm nodes

List of nodes in a server farm indicating that the first in the list is up and running and the second one is down.

The node identified as "farm_member_2" is considered to be down, which indicates that this server has probably failed and requires some maintenance.