Configure Postgres database

If you want to use and manage your own database instead of the default database, you must configure the Postgres database and create the required roles in the database.

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 Postgres configuration file pg_hba.conf for editing by entering the following command:

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

4. Configure Postgres to be accessible from Event Processor and DAS hosts. Add similar lines as follows to the configuration file:

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

5. Edit the Postgres configuration file postgresql.conf by opening and adding the following information:

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

   listen_addresses = '*'

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

   service postgresql-9.6 start

7. Run the following commands to create roles in Postgres:

   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 database password.

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