Your web applications need a solution to store and retrieve its data. A relational database is often used in web applications. MySQL, MariaDB and PostgreSQL are some popular relational databases. There’s also SQLite. Many applications can use any of these relational databases by the virtue of the database layer abstraction. If you are writing your own web application, pick any one database and install it on your web server.

Install The Database

• Install the package.
• Enable and start the database systemd unit.
• Initialize the database server.
• Create databases.
• Create database users and set their passwords.

Connect The Web Application To The Database Server

Install PostgreSQL Server

Fedora and CentOS:

sudo dnf install postgresql-server

Ubuntu 18.04:

sudo apt install postgresql

New Server Initialization

On CentOS 7/Fedora 30:

sudo postgresql-setup initdb

Upgrading From An Older Version

sudo postgresql-setup --upgrade

Administering The Database Server

Managing The postgresql Daemon

Starting PostgreSQL server

sudo systemctl start postgresql

Checking PostgreSQL Server Status:

sudo systemctl status postgresql

Enabling PostgreSQL Server Systemd Unit/Enabling PostgreSQL Server On Boot:

sudo systemctl enable postgresql

Allowing Password Based Login From localhost

Edit /var/lib/pgsql/data/pg_hba.conf as privileged user(root) and add this line:

In this tutorial, I will provide step-by-step process to implement MySQL replication. We will create one master and one slave. We will use two CentOS 6 servers - one for master and the other for slave. This following steps have been tested on two virtual machines.

Our master server will have IP address 192.168.122.10. Our slave server will have IP address 192.168.122.12.

You might want to run SELinux in permissive mode.