After configuring the PostgreSQL, we need to restart PostgreSQL:

1. Enter the command
   systemctl restart postgresql-10
2. After restarting we need to open the default port (5432) using firewall-cmd:
   (root)
   1. firewall-cmd --add-port=5432/tcp --permanent
   2. firewall-cmd --reload
3. Enter the following commands on the primary node ONLY:
   1. su - postgres
   2. psql -c "alter role postgres password '<postgres user password>';"
   3. exit
4. On all nodes create a user (role) in PostgreSQL to perform the replication. The user has to have the replication role on all nodes:
   1. su - postgres
   2. psql -c "CREATE ROLE repuser LOGIN SUPERUSER REPLICATION PASSWORD '<postgres user password>';"
   3. exit
5. Create the REPMGR extension once for each PostgreSQL server:
   1. su - postgres
   2. psql -c "CREATE EXTENSION repmgr;"
   3. exit
6. Finally, we need to update the path in “~/.bash_profile” (user: root). Add the following line to the bash_profile file (Note the commands are case-sensitive):
   1. vi /root/.bash_profile
      Replace “export PATH” with “export PATH=/usr/pgsql-10/bin:$PATH”
   2. source /root/.bash_profile
   3. Validate by running “repmgr”, you will get an error message “cannot be run as root