1<chapter id="follow-new-primary"> 2 <title>Following a new primary</title> 3 4 <indexterm> 5 <primary>Following a new primary</primary> 6 <seealso>repmgr standby follow</seealso> 7 </indexterm> 8 9 <para> 10 Following the failure or removal of the replication cluster's existing primary 11 server, <xref linkend="repmgr-standby-follow"/> can be used to make "orphaned" standbys 12 follow the new primary and catch up to its current state. 13 </para> 14 <para> 15 To demonstrate this, assuming a replication cluster in the same state as the 16 end of the preceding section (<xref linkend="promoting-standby"/>), 17 execute this: 18 <programlisting> 19 $ repmgr -f /etc/repmgr.conf standby follow 20 INFO: changing node 3's primary to node 2 21 NOTICE: restarting server using "pg_ctl -l /var/log/postgresql/startup.log -w -D '/var/lib/postgresql/data' restart" 22 waiting for server to shut down......... done 23 server stopped 24 waiting for server to start.... done 25 server started 26 NOTICE: STANDBY FOLLOW successful 27 DETAIL: node 3 is now attached to node 2 28 </programlisting> 29 </para> 30 <para> 31 The standby is now replicating from the new primary and 32 <command><link linkend="repmgr-cluster-show">repmgr cluster show</link></command> 33 output reflects this: 34 <programlisting> 35 $ repmgr -f /etc/repmgr.conf cluster show 36 ID | Name | Role | Status | Upstream | Location | Connection string 37 ----+-------+---------+-----------+----------+----------+-------------------------------------- 38 1 | node1 | primary | - failed | | default | host=node1 dbname=repmgr user=repmgr 39 2 | node2 | primary | * running | | default | host=node2 dbname=repmgr user=repmgr 40 3 | node3 | standby | running | node2 | default | host=node3 dbname=repmgr user=repmgr</programlisting> 41 </para> 42 <para> 43 Note that with cascading replication, <command>repmgr standby follow</command> can also be 44 used to detach a standby from its current upstream server and follow the 45 primary. However it's currently not possible to have it follow another standby; 46 we hope to improve this in a future release. 47 </para> 48 49</chapter> 50