Resilience

On October 20, 2025, DNS resolution failed in AWS us-east-1, and with it, a lot of DynamoDB applications went down. Not because DynamoDB itself failed. The service was running. Data was there. Capacity was fine. But applications couldn’t reach it because DNS queries for dynamodb.us-east-1.amazonaws.com stopped resolving correctly. If you’ve ever wondered what happens when the infrastructure layer beneath your supposedly resilient database becomes unreachable—October 20 was the answer. And it wasn’t pretty. ...

On the morning of October 20, AWS us-east-1 services were degraded—in particular, DNS services for DynamoDB. Most of us didn’t find out from monitoring alerts or dashboards. We found out because the apps on our phones stopped working. That’s the reality of modern infrastructure incidents: they often surface as user-facing failures long before the official root cause analysis lands in your inbox. I wrote about this outage for Ippon Technologies, focusing on three critical aspects that go beyond just understanding what broke: ...