ltclusterd is a daemon process which runs on each LightDB node, monitoring the local node, and (unless it's the primary node) the upstream server (the primary server or with cascading replication, another standby) which it's connected to.

ltclusterd can be configured to provide failover capability in case the primary or upstream node becomes unreachable, and/or provide monitoring data to the ltcluster metadatabase.

From ltcluster 4.4, when running on the primary node, ltclusterd can also monitor standby disconnections/reconnections (see Monitoring standby disconnections on the primary).