AWS randomly assigns AZ names differently across accounts

Been like this for the longest time.

Makes sense but a real PITA when using a lot of AWS accounts in an org.

In hindsight they should have assigned AZ identifiers to something less sequential.

Instead of

eu-east-1, eu-east-2, eu-east-3

Do something like

eu-east-s, eu-east-k, eu-east-p

where the suffixes are the same for everyone. Less bias to choosing -1 then.

To prevent the effect of people picking the first zone in the list to launch resources into

Exactly this. If they didn’t do this, us-east-1a would be the biggest single point of failure the world has ever seen.

Yeah. There is an api call that shows the mapping between a region's az names and the static az id's. I wasn't an early adopter but encountered the random az assignment in 2010.