I understand this is long-since resolved (I haven't tried building a service on Amazon in a couple years, so this isn't personal experience), but centralized failure modes in decentralized systems can persist longer than you might expect.
(Work for Google, not on Cloud or anything related to this outage that I'm aware of, I have no knowledge other than reading the linked outage page.)
Maybe you mean region, because there is no way that AWS tools were ever hosted out of a single zone (of which there are 4 in us-east-1). In fact, as of a few years ago, the web interface wasn’t even a single tool, so it’s unlikely that there was a global outage for all the tools.
And if this was later than 2012, even more unlikely, since Amazon retail was running on EC2 among other services at that point. Any outage would be for a few hours, at most.
"Some services, such as IAM, do not support Regions; therefore, their endpoints do not include a Region."
There was a partial outage maybe a month and a half ago where our typical AWS Console links didn't work but another region did. My understanding is that if that outage were in us-east-1 then making changes to IAM roles wouldn't have worked.
Your quote cd mean two things.
- that IAM services are hosted in one region (not one AZ)
- that IAM is for the entire account not per region like other services (which is true)