It reminds me of facebook. Staff was locked out of the office due to the outage they were supposed to fix.

It's basically what leads to extended downtime almost every time. There are just some things in the stack that are still single points of failure, and when they fail it's a mess.

when you have a circular dependency, one strategy employed, is to have it be circular but interruptible for 18 or so hours. Call it an oh shit bar.

I'm glad I never had to get that deep into the failure chain.