First update the server.

yum update -y ; yum upgrade -y

Install MariaDB and start the server (as root)

yum install mariadb-server
systemctl start mariadb

To check MariaDB status

systemctl status mariadb

The output should be like this

Dec 01 19:06:20 centos-512mb-sfo2-01 systemd[1]: Started MariaDB database server.

To enable MariaDB on boot simply

systemctl enable mariadb

To secure MariaDB install


Testing the installation

mysqladmin -u root -p version