promoting a standby repmgr standby promote If a primary server fails or needs to be removed from the replication cluster, a new primary server must be designated, to ensure the cluster continues to function correctly. This can be done with , which promotes the standby on the current server to primary. To demonstrate this, set up a replication cluster with a primary and two attached standby servers so that the cluster looks like this: $ repmgr -f /etc/repmgr.conf cluster show ID | Name | Role | Status | Upstream | Location | Connection string ----+-------+---------+-----------+----------+----------+-------------------------------------- 1 | node1 | primary | * running | | default | host=node1 dbname=repmgr user=repmgr 2 | node2 | standby | running | node1 | default | host=node2 dbname=repmgr user=repmgr 3 | node3 | standby | running | node1 | default | host=node3 dbname=repmgr user=repmgr Stop the current primary with e.g.: $ pg_ctl -D /var/lib/postgresql/data -m fast stop At this point the replication cluster will be in a partially disabled state, with both standbys accepting read-only connections while attempting to connect to the stopped primary. Note that the &repmgr; metadata table will not yet have been updated; executing will note the discrepancy: $ repmgr -f /etc/repmgr.conf cluster show ID | Name | Role | Status | Upstream | Location | Connection string ----+-------+---------+---------------+----------+----------+-------------------------------------- 1 | node1 | primary | ? unreachable | | default | host=node1 dbname=repmgr user=repmgr 2 | node2 | standby | running | node1 | default | host=node2 dbname=repmgr user=repmgr 3 | node3 | standby | running | node1 | default | host=node3 dbname=repmgr user=repmgr WARNING: following issues were detected node "node1" (ID: 1) is registered as an active primary but is unreachable Now promote the first standby with: $ repmgr -f /etc/repmgr.conf standby promote This will produce output similar to the following: INFO: connecting to standby database NOTICE: promoting standby DETAIL: promoting server using "pg_ctl -l /var/log/postgresql/startup.log -w -D '/var/lib/postgresql/data' promote" server promoting INFO: reconnecting to promoted server NOTICE: STANDBY PROMOTE successful DETAIL: node 2 was successfully promoted to primary Executing will show the current state; as there is now an active primary, the previous warning will not be displayed: $ repmgr -f /etc/repmgr.conf cluster show ID | Name | Role | Status | Upstream | Location | Connection string ----+-------+---------+-----------+----------+----------+-------------------------------------- 1 | node1 | primary | - failed | | default | host=node1 dbname=repmgr user=repmgr 2 | node2 | primary | * running | | default | host=node2 dbname=repmgr user=repmgr 3 | node3 | standby | running | node1 | default | host=node3 dbname=repmgr user=repmgr However the sole remaining standby (node3) is still trying to replicate from the failed primary; must now be executed to rectify this situation (see for example).