Enables a dormant (stopped) node to be rejoined to the replication cluster.
This can optionally use pg_rewind to re-integrate a node which has diverged from the rest of the cluster, typically a failed primary.
Tip: If the node is running and needs to be attached to the current primary, use repmgr standby follow.
repmgr node rejoin -d '$conninfo'
where $conninfo is the conninfo string of any reachable node in the cluster. repmgr.conf for the stopped node *must* be supplied explicitly if not otherwise available.
Check prerequisites but don't actually execute the rejoin.
Execute pg_rewind if necessary.
It is only necessary to provide the pg_rewind if using PostgreSQL 9.3 or 9.4, and pg_rewind is not installed in the PostgreSQL bin directory.
comma-separated list of configuration files to retain after executing pg_rewind.
Currently pg_rewind will overwrite the local node's configuration files with the files from the source node, so it's advisable to use this option to ensure they are kept.
Directory to temporarily store configuration files specified with --config-files; default: /tmp.
Don't wait for the node to rejoin cluster.
If this option is supplied, repmgr will restart the node but not wait for it to connect to the primary.
Currently repmgr node rejoin can only be used to attach a standby to the current primary, not another standby.
The node must have been shut down cleanly; if this was not the case, it will need to be manually started (remove any existing recovery.conf file first) until it has reached a consistent recovery point, then shut down cleanly.
Tip: If PostgreSQL is started in single-user mode and input is directed from /dev/null/, it will perform recovery then immediately quit, and will then be in a state suitable for use by pg_rewind.
rm -f /var/lib/pgsql/data/recovery.conf postgres --single -D /var/lib/pgsql/data/ < /dev/null
repmgr node rejoin can optionally use pg_rewind to re-integrate a node which has diverged from the rest of the cluster, typically a failed primary. pg_rewind is available in PostgreSQL 9.5 and later as part of the core distribution, and can be installed from external sources for PostgreSQL 9.3 and 9.4.
Note: pg_rewind requires that either wal_log_hints is enabled, or that data checksums were enabled when the cluster was initialized. See the pg_rewind documentation for details.
To have repmgr node rejoin use pg_rewind if required, pass the command line option --force-rewind, which will tell repmgr to execute pg_rewind to ensure the node can be rejoined successfully.
Be aware that if pg_rewind is executed and actually performs a rewind operation, any configuration files in the PostgreSQL data directory will be overwritten with those from the source server.
To prevent this happening, provide a comma-separated list of files to retain using the --config-file command line option; the specified files will be archived in a temporary directory (whose parent directory can be specified with --config-archive-dir) and restored once the rewind operation is complete.
Example, first using --dry-run, then actually executing the node rejoin command.
$ repmgr node rejoin -f /etc/repmgr.conf -d 'host=node1 dbname=repmgr user=repmgr' \
--force-rewind --config-files=postgresql.local.conf,postgresql.conf --verbose --dry-run
NOTICE: using provided configuration file "/etc/repmgr.conf"
INFO: prerequisites for using pg_rewind are met
INFO: file "postgresql.local.conf" would be copied to "/tmp/repmgr-config-archive-node1/postgresql.local.conf"
INFO: file "postgresql.conf" would be copied to "/tmp/repmgr-config-archive-node1/postgresql.local.conf"
INFO: 2 files would have been copied to "/tmp/repmgr-config-archive-node1"
INFO: directory "/tmp/repmgr-config-archive-node1" deleted
INFO: pg_rewind would now be executed
DETAIL: pg_rewind command is:
pg_rewind -D '/var/lib/postgresql/data' --source-server='host=node1 dbname=repmgr user=repmgr'
$ repmgr node rejoin -f /etc/repmgr.conf -d 'host=node1 dbname=repmgr user=repmgr' \
--force-rewind --config-files=postgresql.local.conf,postgresql.conf --verbose
NOTICE: using provided configuration file "/etc/repmgr.conf"
INFO: prerequisites for using pg_rewind are met
INFO: 2 files copied to "/tmp/repmgr-config-archive-node1"
NOTICE: executing pg_rewind
NOTICE: 2 files copied to /var/lib/pgsql/data
INFO: directory "/tmp/repmgr-config-archive-node1" deleted
INFO: deleting "recovery.done"
INFO: setting node 1's primary to node 2
NOTICE: starting server using "pg_ctl-l /var/log/postgres/startup.log -w -D '/var/lib/pgsql/data' start"
waiting for server to start.... done
server started
NOTICE: NODE REJOIN successful
DETAIL: node 1 is now attached to node 2