My us-east-1a is NOT your us-east-1a…

Not too long ago I was attending one of the AWS Raleigh Meetups.  The topic was an overview of EC2…

The speaker happened to mention that when provisioning instances, the AZ tagged us-east-la in one account wouldn’t be the same as another account.

Now, I had heard this before, but I’d actually forgotten about it.

Sure enough, the docs confirm that.

To ensure that resources are distributed across the Availability Zones for a region, we independently map Availability Zones to identifiers for each account. For example, your Availability Zone us-east-1a might not be the same location as us-east-1a for another account. There’s no way for you to coordinate Availability Zones between accounts.

While I completely understand AWS’ reasoning for operating in this manner,  I could imagine scenarios when it could be beneficial to be able to coordinate between accounts…certain phases of company mergers, for example. Perhaps an option to Launch in same region as arn:aws:ec2:us-east-1… would be handy.