Liberty leadership configuration
In a deployment with multiple Liberty servers, one server is determined to be the leader.
Liberty leadership behavior
- Initiating Solr indexing
- Initiating online upgrade tasks
- Initiating alerts for saved Visual Queries
- Initiating deletion-by-rule jobs
Leadership stateZooKeeper is used to determine and manage the leadership state of the Liberty servers in a deployment. Each Liberty server polls ZooKeeper for the current leadership state. If there is no leader, the Liberty attempts to become the leader. One Liberty will successfully become the leader.
To become a leader, and to maintain leadership, Liberty must be able to connect to ZooKeeper, Solr, and the database management system. The connection to each component is checked whenever the leadership state is polled. If any of the components cannot be connected to, the Liberty either releases its leadership or cannot run for leader if there is not currently a leader.
The leadership poll schedule is independent on each Liberty server. If the current leader releases its leadership, there is no leader until the leadership poll runs on another Liberty that can then assume leadership status.
leadership poll is completed on a configurable
schedule. By default, the leadership state is
checked every five minutes. To change the
interval, update the value for the
The leadership state can change if a certain number of errors are encountered during indexing operations within a specified time span. These types of operations are run only on the leader Liberty. The maximum number of errors that can occur, and the time span in which they can occur, are configurable.
setting defines the maximum number of errors that
can occur in the time specified by the
setting. By default, up to five errors can occur
within 30 seconds before the Liberty relinquishes
If the leader Liberty releases leadership, it
attempts to restart in non-leader mode. If Liberty
cannot connect to each component, it fails to
start. By default, it tries to start three times
before failing. To start Liberty on this server
again, resolve the issue that is stopping Liberty
connecting to all of the components and run
setup -t startLiberty.