Adding Cross Zone Load Balancing in AWS

One of the new hotness features that Amazon added to their Elastic Load Balancers is cross zone load balancing. This offers the ability to have an unbalanced number of nodes per availability zone within an Amazon region. For instance, if you were load balances across us-east-1a, us-east-1b, and us-east-1c, then you needed to have the same number of instances in each zone otherwise the traffic would skew and overload the zone with fewer instances. If you are auto-scaling, using spots, or just happen to lose instances from time to time, you can easily see where this becomes a problem. Read the rest of this entry »