From: https://webtatic.com/packages/mysql55/

First, to set up the yum repository, install the webtatic-release RPM based on your CentOS/RHEL release:

Webtatic EL6 for CentOS/RHEL 6.x

rpm -Uvh https://mirror.webtatic.com/yum/el6/latest.rpm

Webtatic EL5.1 for CentOS/RHEL 5.x:

rpm -Uvh http://mirror.webtatic.com/yum/el5/latest.rpm

If you already have MySql client or server installed (rpm -q mysql mysql-server), then you can upgrade using the following method:

yum install mysql.`uname -i` yum-plugin-replaceyum replace mysql --replace-with mysql55w

“yum install mysql” is only there to make sure yum-plugin-replace can resolve dependencies correctly if only mysql-server was installed.

Otherwise, to install MySql client and server, then run:

yum install mysql55w mysql55w-server

You should upgrade existing tables before setting the server to become a production machine, which can be done by starting the server and running the mysql_upgrade script (this may take time depending on the size of the database).

service mysqld start

# This will issue a password prompt for the user. If you don't have a root user password, remove the "-p"

 mysql_secure_installation