For Ubuntu

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:

   echo deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg main > /etc/apt/sources.list.d/postgresql.list

   wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -

   apt-get update

   apt-get install postgresql-9.6

   For more information about the supported version of Postgres, see the DAS Support Matrix.

2. To make Postgres accessible to the DAS webapp and the DAS event processor host:
   1. Open the pg_hba.conf file for editing.

      vi /var/lib/postgresql/9.6/main/pg_hba.conf

   2. 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
      

   3. Open the postgresql.conf file for editing.

      vi /var/lib/postgresql/9.6/main/postgresql.conf

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

      listen_addresses = '*'

3. Start the Postgres database by running the following command as a Postgres user:

   /usr/lib/postgresql/9.6/bin/pg_ctl start -D /var/lib/postgresql/9.6/main/

4. 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.