1. Initialize the database folder “/var/lib/pgsql/10/data” using the following command. Please keep in mind that the Linux user “postgres” has the data directory already configured as an environment variable called “$PGDATA”:
    sudo -u postgres /usr/pgsql-10/bin/initdb -D /var/lib/pgsql/10/data
  2. Change the following configurations in the “/var/lib/pgsql/10/data/postgresql.conf” configuration file as follows: (Make sure to remove the comments #) 
     wal_level = replica archive_mode = on archive_command = ‘/bin/true’ max_wal_senders = 10 wal_sender_timeout = 3600s max_replication_slots = 10 hot_standby = on hot_standby_feedback = on autovacuum = on work_mem = 24MB shared_buffers = 12GB max_connections = 1000 listen_addresses = ‘*’ shared_preload_libraries = ‘repmgr’ wal_log_hints = on

    If you want more information on these parameters, please look here:
    The parameter descriptions you can find in this link:
    https://www.postgresql.org/docs/10/runtime-config.html
    https://www.postgresql.org/docs/10/runtime-config-replication.html – (for Replication)

    Note that the configuration above is for VM with 12 CPUs and 32GB RAM and is based on the following:

    VM Type shared_buffers work_mem max_worker_processes
    2 CPU \ 8GB RAM 2GB 4MB 2
    8 CPU \ 16GB RAM 3GB 6MB 8
    12 CPU \ 32GB RAM 12GB 24MB 8
  3. Next, we need to add more rule to the “/var/lib/pgsql/10/data/pg_hba.conf” file to accept all connections from all sources. Note that Siemplify recommends typing it into the file and not copy/pasting it.

    IPv4 local connections:
    host all all 0.0.0.0/0 md5
    host replication all 0.0.0.0/0 md5

  4. Finally, we need to add “postgres” as a sudoer for the “system_start_command” in repmgr as follows. Add a new text file “/etc/sudoers.d/postgres” which contains the following:
    Defaults:postgres !requiretty postgres ALL = NOPASSWD: /usr/bin/systemctl stop postgresql-10,/usr/bin/systemctl start postgresql-10,/usr/bin/systemctl restart postgresql-10,/usr/bin/systemctl reload postgresql-10