So the backbone of my webcluster i use Heartbeat to monitor the server performance.
Heartbeat is setup to monitor the servers and to take actions if anything happens with some of the nodes.
This guide is for migraing and ip addres from one node to the secondary of the first node goes down.
Then i configure the other servers like apache ore mysql ontop.
First begin to enabling EPEL repos.
rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
Install heartbeat
yum install heartbeat
Setup so your host fiile is ok
10.20.0.21 web1 10.20.0.22 web2
Create the file /etc/ha.d/ha.cf and ad the following in it
keepalive 2 deadtime 30 bcast eth0 node web1 web2
Create the file vi /etc/ha.d/haresources and ad the following into it
web1 IPaddr::10.0.0.100/24/eth0
The ip 10.0.0.100 is the ip that will first be in web1. If web1 goes down the ip will be transfer to web2 that will take over the reqest.
Create the file vi /etc/ha.d/authkeys and fill it with (alter the password)
auth 3 3 md5 password6asd567hajksdhjkhkjjkahdsk
Setting correct chmod to authkeys
chmod 600 /etc/ha.d/authkeys
Copy the config files to your heartbeat nodes. And then restart you heartbeat service
/etc/init.d/heartbeat restart
And run an ifconfig to se where your ip is
ifconfig
And thats it. Now when you first node is down the ip will come up at your secondary server.