For this cluster, we will use FreeBSD 4.9. Why? Simply because. This is not because FreeBSD is better than Linux is better than Solaris is better the Joe's OS, and so on. Honestly, any of these Unix and Unix-like systems should work like a charm. So, why do we choose FreeBSD as an example?
We install six commodity servers with a FreeBSD 4.9 default install and assign each its public management IP address, 192.0.2.11 through 192.0.2.16, and name them image-0-1 through image-0-6, respectively.
Appropriate firewall rules should be set to protect these machines. Although this is outside the scope of this book, we can discuss the traffic we expect to originate from and terminate at each box.
It is important to note that the six IP addresses above the management IPs and all client-originating web traffic will arrive to the IP published through DNS for this service.