CentOS5
# rpm -ivh http://dev.mysql.com/get/mysql-community-release-el5-5.noarch.rpm
CentOS6
# rpm -ivh http://dev.mysql.com/get/mysql-community-release-el6-5.noarch.rpm
CentOS7
# rpm -ivh http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm
# yum install mysql-community-server