For CentOS

The commands to configure Postgres database are different for CentOS, Debian, and Ubuntu. Refer to the respective section to view the procedure for your platform.

1. Install the supported version of Postgres using the following commands:

   yum install https://download.postgresql.org/pub/repos/yum/9.6/redhat/rhel-7-x86_64/pgdg-centos96-9.6-3.noarch.rpm

   yum install postgresql96-contrib postgresql96-server

   For more information about the supported version of Postgres, see the DAS Support Matrix.
2. Initialize the Postgres database by running the following command:

   service postgresql-9.6 initdb

3. Open the pg_hba.conf file for editing by entering the following command:

   vi /var/lib/pgsql/9.6/data/pg_hba.conf

4. Add lines similar to the following lines:

   local   all             <dbuser>                              md5
   host    all             <dbuser>      0.0.0.0/0               md5
   host    all             <dbuser>      ::/0                    md5
   local   all             postgres         ident
   

5. Open the postgresql.conf file for editing.

   vi /var/lib/pgsql/9.6/data/postgresql.conf

6. Add, update, or uncomment the listen_addresses line as follows:

   listen_addresses = '*'

7. Start the Postgres database by running the following command:

   service postgresql-9.6 start

8. Create roles in Postgres by running the following commands as a Postgres user:

   psql -tc "SELECT 1 FROM pg_database WHERE datname = <dbuser>" | grep 1 || (
   psql -c "CREATE ROLE <dbuser> WITH LOGIN PASSWORD <dbpass>;" &&
   psql -c "ALTER ROLE <dbuser> SUPERUSER;" &&
   psql -c "ALTER ROLE <dbuser> CREATEDB;" &&
   psql -c "CREATE DATABASE <dbuser>;" &&
   psql -c "GRANT ALL PRIVILEGES ON DATABASE <dbuser> TO <dbuser>;")

   Replace <dbuser> with the database username/database name and <dbpass> with the database password.

   	Note
   	The database user and database name must be the same. It should be the one that is used as the database username in the DAS configuration on Ambari.