You pay for cross-AZ Traffic in AWS, and that adds up really fast.
Our fault, I suppose -- but multi-az is prohibitively expensive if you need to run anything data heavy distributed.
> but multi-az is prohibitively expensive if you need to run anything data heavy distributed.
If you communicate between your AZs via ALBs, multi-az is effectively free. Our bill is so high because within our Kubernetes cluster, our mesh isn't locality aware; it randomly routes to any available pod. 2/3rds of our traffic crosses AZs.
It's nobody's fault that the billing structure at Amazon is so complicated and confusing.
Except Amazon's.