Following the failure or removal of the replication cluster's existing primary server, ltcluster standby follow can be used to make "orphaned" standbys follow the new primary and catch up to its current state.

To demonstrate this, assuming a replication cluster in the same state as the end of the preceding section (Promoting a standby), execute this:

    $ ltcluster -f /etc/ltcluster.conf standby follow
    INFO: changing node 3's primary to node 2
    NOTICE: restarting server using "lt_ctl -l /var/log/lightdb/startup.log -w -D '/var/lib/lightdb/data' restart"
    waiting for server to shut down......... done
    server stopped
    waiting for server to start.... done
    server started
    NOTICE: STANDBY FOLLOW successful
    DETAIL: node 3 is now attached to node 2
  

The standby is now replicating from the new primary and ltcluster cluster show output reflects this:

    $ ltcluster -f /etc/ltcluster.conf cluster show
     ID | Name  | Role    | Status    | Upstream | Location | Connection string
    ----+-------+---------+-----------+----------+----------+--------------------------------------
     1  | node1 | primary | - failed  |          | default  | host=node1 dbname=ltcluster user=ltcluster
     2  | node2 | primary | * running |          | default  | host=node2 dbname=ltcluster user=ltcluster
     3  | node3 | standby |   running | node2    | default  | host=node3 dbname=ltcluster user=ltcluster

Note that with cascading replication, ltcluster standby follow can also be used to detach a standby from its current upstream server and follow the primary. However it's currently not possible to have it follow another standby; we hope to improve this in a future release.