An example playbook to install MySQL and configure the MySQL root password on Centos 6.x .

ex-mysql-playbook.yml

---
- hosts: all # Replace this with your database's host/group
  vars:
      mysql_password: xxxxxxxx # Replace this with your root mysql password
      epel_repo: epel-release-6-8.noarch.rpm
  sudo: yes
  tasks: 
  
  # The EPEL repository is required to install Python pip
  - name: Download EPEL-repo rpm for CentOS 6.x
    get_url: dest=/tmp/{{ epel_repo }}
        url=http://download.fedoraproject.org/pub/epel/6/{{ ansible_architecture }}/{{ epel_repo }}

  - name: Install EPEL-repo rpm
    yum: pkg=/tmp/{{ epel_repo }} state=installed

  - name: Ensure Python pip is at the latest version
    yum: pkg=python-pip state=latest

  - name: Ensure MySQL server is at the latest version
    yum: pkg=mysql-server state=latest

  - name: Start mysqld, if not running
    service: name=mysqld state=started

  - name: Ensure MySQL-Python is at the latest version
    yum: pkg=MySQL-python state=latest

  - name: Install ConfigParser Python package
    pip: name=configparser

  # This step is required to run the template module
  - name: Ensure libselinux-python is at the latest version
    yum: pkg=libselinux-python state=latest

  - name: Set the root user for MYSQL
    mysql_user: name=root password={{ mysql_password }}

  - name: Copy the ".my.cnf" file
    template: src=my.cnf.j2 dest=~/.my.cnf mode=0600 

my.cnf.j2

[client]
user=root
password={{ mysql_password }}