repmgr/QUICKSTART.md

repmgr quickstart guide

This quickstart guide provides some annotated examples on basic repmgr setup. It assumes you are familiar with PostgreSQL replication concepts setup and Linux/UNIX system administration.

For the purposes of this guide, we'll assume the database user will be repmgr_usr and the database will be repmgr_db.

Master setup

1. Configure PostgreSQL

• create user and database:

  CREATE ROLE repmgr_usr LOGIN SUPERUSER;
  CREATE DATABASE repmgr_db OWNER repmgr_usr;
  

• configure postgresql.conf for replication (see above)

• update pg_hba.conf, e.g.:

  host    repmgr_db       repmgr_usr  192.168.1.0/24         trust
  host    replication     repmgr_usr  192.168.1.0/24         trust
  

Restart the PostgreSQL server after making these changes. 2. Create the repmgr configuration file:

    $ cat /path/to/repmgr/node1/repmgr.conf
    cluster=test
    node=1
    node_name=node1
    conninfo='host=repmgr_node1 user=repmgr_usr dbname=repmgr_db'
    pg_bindir=/path/to/postgres/bin

(For an annotated repmgr.conf file, see repmgr.conf.sample in the repository's root directory).

3. Register the master node with repmgr:

    $ repmgr -f /path/to/repmgr/node1/repmgr.conf --verbose master register
    [2015-03-03 17:45:53] [INFO] repmgr connecting to master database
    [2015-03-03 17:45:53] [INFO] repmgr connected to master, checking its state
    [2015-03-03 17:45:53] [INFO] master register: creating database objects inside the repmgr_test schema
    [2015-03-03 17:45:53] [NOTICE] Master node correctly registered for cluster test with id 1 (conninfo: host=localhost user=repmgr_usr dbname=repmgr_db)
   

Standby setup

1. Use repmgr standby clone to clone a standby from the master:

    repmgr -D /path/to/standby/data -d repmgr_db -U repmgr_usr --verbose standby clone 192.168.1.2
    [2015-03-03 18:18:21] [NOTICE] No configuration file provided and default file './repmgr.conf' not found - continuing with default values
    [2015-03-03 18:18:21] [NOTICE] repmgr Destination directory ' /path/to/standby/data' provided
    [2015-03-03 18:18:21] [INFO] repmgr connecting to upstream node
    [2015-03-03 18:18:21] [INFO] repmgr connected to upstream node, checking its state
    [2015-03-03 18:18:21] [INFO] Successfully connected to upstream node. Current installation size is 27 MB
    [2015-03-03 18:18:21] [NOTICE] Starting backup...
    [2015-03-03 18:18:21] [INFO] creating directory " /path/to/standby/data"...
    [2015-03-03 18:18:21] [INFO] Executing: 'pg_basebackup -l "repmgr base backup"  -h localhost -p 9595 -U repmgr_usr -D  /path/to/standby/data '
    NOTICE:  pg_stop_backup complete, all required WAL segments have been archived
    [2015-03-03 18:18:23] [NOTICE] repmgr standby clone (using pg_basebackup) complete
    [2015-03-03 18:18:23] [NOTICE] HINT: You can now start your postgresql server
    [2015-03-03 18:18:23] [NOTICE] for example : pg_ctl -D  /path/to/standby/data start
   

Note that at this point it does not matter if the repmgr.conf file is not found.

This will clone the PostgreSQL database files from the master, including its postgresql.conf and pg_hba.conf files, and additionally automatically create the recovery.conf file containing the correct parameters to start streaming from the primary node.

2. Start the PostgreSQL server

3. Create the repmgr configuration file:

    $ cat /path/node2/repmgr/repmgr.conf
    cluster=test
    node=2
    node_name=node2
    conninfo='host=repmgr_node2 user=repmgr_usr dbname=repmgr_db'
    pg_bindir=/path/to/postgres/bin
   

4. Register the standby node with repmgr:

    $ repmgr -f /path/to/repmgr/node2/repmgr.conf --verbose standby register
    [2015-03-03 18:24:34] [NOTICE] Opening configuration file: /path/to/repmgr/node2/repmgr.conf
    [2015-03-03 18:24:34] [INFO] repmgr connecting to standby database
    [2015-03-03 18:24:34] [INFO] repmgr connecting to master database
    [2015-03-03 18:24:34] [INFO] finding node list for cluster 'test'
    [2015-03-03 18:24:34] [INFO] checking role of cluster node '1'
    [2015-03-03 18:24:34] [INFO] repmgr connected to master, checking its state
    [2015-03-03 18:24:34] [INFO] repmgr registering the standby
    [2015-03-03 18:24:34] [INFO] repmgr registering the standby complete
    [2015-03-03 18:24:34] [NOTICE] Standby node correctly registered for cluster test with id 2 (conninfo: host=localhost user=repmgr_usr dbname=repmgr_db)
   

This concludes the basic repmgr setup of master and standby. The records created in the repl_nodes table should look something like this:

    repmgr_db=# SELECT * from repmgr_test.repl_nodes;
     id |  type   | upstream_node_id | cluster | name  |                     conninfo                    | slot_name | priority | active
    ----+---------+------------------+---------+-------+-------------------------------------------------+-----------+----------+--------
      1 | primary |                  | test    | node1 | host=localhost user=repmgr_usr dbname=repmgr_db |           |        0 | t
      2 | standby |                1 | test    | node2 | host=localhost user=repmgr_usr dbname=repmgr_db |           |        0 | t
    (2 rows)