Install_configure_PostgreSQL_CENTOS7.md

The following steps will let you install, configure PostgreSQL server and create a hil database for development or production version of HIL on a Centos - 7 server.

For simplicity of configuration and ease of maintenance we will use single name hil for creating a system user, database role and database name. This is merely a guideline for users new to database setup and administration. Experienced users are free to choose any other method that suits their need. The end goal is to have a way to have a working PostgreSQL backend for hil

Part 1: Install PostgreSQL server.

Initialize the system. Configure PostgreSQL to allow password authentication.

1. Install the requisite packages on your server.

sudo yum install postgresql-server postgresql-contrib -y

2. Initialize postgresql:

sudo postgresql-setup initdb

3. Replace the term ident from following lines in file /var/lib/pgsql/data/pg_hba.conf with md5

Before:

# "krb5", "ident", "peer", "pam", "ldap", "radius" or "cert".  Note that
host    all             all             127.0.0.1/32            ident
host    all             all             ::1/128                 ident
#host    replication     postgres        127.0.0.1/32            ident
#host    replication     postgres        ::1/128                 ident

After:

# "krb5", "ident", "peer", "pam", "ldap", "radius" or "cert".  Note that
host    all             all             127.0.0.1/32            md5
host    all             all             ::1/128                 md5
#host    replication     postgres        127.0.0.1/32            ident
#host    replication     postgres        ::1/128                 ident

4. Start postgresql service

$ sudo systemctl start postgresql
$ sudo systemctl enable postgresql

##Part 2: Setup system user and database role for HIL.

Create database named hil owned by user also named as hil.

5. Create a system user hil:

If you are setting up this database for a production setup then you might have already created a system user for managing HIL. In that case skip this step.

If you are setting up database for development purpose you will need to create a system user to manage HIL database as follows.

format: useradd <username> --system -d <path-to-home-dir> -m -r

In this case both system username and home directory will be named hil

useradd hil --system -d /var/lib/hil -m -r

6. Create a database role named hil with privileges to: -r create roles -d create databases and -P will prompt for the password of the new user. This is necessary since we have configured PostgreSQL to use password authentication.

$ sudo -u postgres createuser -r -d -P hil
Enter password for new role:  <Input password for database role hil>
Enter it again: <Retype password for role hil>

Confirm that the role with requisite privileges is created as postgres user:

$ psql -c '\dg'
                             List of roles
 Role name |                   Attributes                   | Member of
-----------+------------------------------------------------+-----------
 hil      | Create role, Create DB                         | {}
 postgres  | Superuser, Create role, Create DB, Replication | {}

Note: It is recommended that the PostgreSQL role and database you create correspond to an existing system user. eg. There should be a system user hil to access database named hil as database role named hil. Advanced user/role/database configurations may not need to follow this rule. More information is available in the Database Roles and Privileges reference guide.

7. Create database hil owned by database role hil:

sudo -u hil createdb hil

confirm it created a database named hil and it is owned by hil.

$ psql -c '\l'
                                  List of databases
   Name    |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
 hil      | hil     | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 postgres  | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 template0 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres

##Finally:

If you have followed all steps so far. Put following string in hil.cfg under section [database]

uri = postgresql://hil:<clear text password >@localhost:5432/hil

It follows the format: postgresql://<user>:<password>@<address>/<dbname> where <user> is the name of the postgres user you created, <password> is its password, <dbname> is the name of the database you created, and <address> is the address which hil should use to connect to postgres (In a typical default postgres setup, the right value is localhost).

Continue with installation steps:

continue with production install or continue with development install