One Zone Died and the Multi-Zone Application Went Down Anyway
The provider reports degraded power and network in zone A of our region. Our application runs in three zones with instances in each, exactly as designed. Two thirds of the fleet is healthy and serving. And the site is down: every request that touches the database fails, and every outbound call to the mail and payment providers times out.
The infrastructure under investigation
Exposure is shown, because half of these failures are a reachability question.
Pull evidence
One item at a time, and nothing here tells you which one matters. Deciding what is worth looking at is most of the diagnosis.
0 of 9 inspected. You are not required to open all of them — a real investigation is judged on how few you needed.
What is your diagnosis?
Commit to one. Nothing below is shown until you do.
Guessing wrong and being told exactly why is the point of this page. Reading the answer first is not practice.