Apache

Running a redundant apache server does not require much from apache itself, but rather the underlying filesystem and a proxy in front of it. The filesystem is important, so the website and its php sessions can be shared between the servers. For this we will use GlusterFS. The proxy in front of apache will be a combination of HA-proxy and Corosync.

In this setup we will configure 2 apache servers. None of these will be master/slave/primary/secondary. They will just be running with the same configuration. Since the servers are configure the same way it makes sense to share some files.

• 192.168.1.50 www01
• 192.168.1.51 www02

Software

apt-get install apache2 php php-mysql

Filesystem

Configure your system as a GlusterFS client, so you have the following in your fstab.

/etc/glusterfs/www.vol /var/www glusterfs defaults,_netdev,rw 0 0

Testpage

Make a simple webpage, that shows something unique about the system. This is usefull when debugging. index.php

   1 <?php
   2         echo "client: " . $_SERVER['REMOTE_ADDR'] . "\n";
   3         echo "server: " . $_SERVER['SERVER_ADDR'] . "\n";
   4         echo "hostname: " . gethostname() . "\n";
   5 ?>