IP addresses to set up fault tolerance?
Why do I need so many IP addresses to set up fault tolerance? There are three 'classes' of IP addresses that we use: 1) 'Front-end' IP addresses - think of these as what are the current IP addresses of each of the Load Balancer machines. Each machine must have a unique IP address to identify itself, so you can contact it directly. '2) Traffic' IP addresses - these are the addresses of your load balancers that the outside world will see and know about. You need at least two of these (so the balancers can have an address each). Unlike the 'front-end' IP addresses, traffic IP addresses are not tied to one machine - they get shared around and moved. For instance, if one of the balancer machines dies, then the other balancer will take its traffic IP address. This way, visitors will always be able to reach your site. '3) Back-end' IP addresses - the balancer machines use these IP addresses to contact the back-end servers. The balancer