# AWS outage post-mortem fingers DNS as the culprit

Source: https://www.tomshardware.com/tech-industry/big-tech/massive-amazon-web-service-outage-that-took-out-a-chunk-of-the-internet-and-services-for-days-was-due-to-dns-automation-systems-race-and-crash

## Summary

The AWS outage post-mortem attributes the failure to DNS, according to Amazon's detailed technical write-up of the incident. The outage lasted about three hours, from October 19 at 11:48 PM to October 20 at 2:40 AM, and the initial problem was fixed relatively quickly. Dependent services kept breaking afterward, however, and took much longer to fully recover, in an effect the article compares to a traffic jam that outlasts the crash.

## Article

The recent Amazon Web Services outage that took out a significant portion of the internet, games, and even smart home devices for days, was extensively covered in the news. Cloud services' distributed architecture should protect customers from failures like this one, so what went wrong? Amazon published a detailed technical post-mortem of the failure, and as the famous haiku poem goes: "It's not DNS. / There's no way it's DNS. / It was DNS."

As a rough analogy, consider what happens when there's a car crash. There's a traffic jam that stretches for miles, in an accordion-like effect that lasts well after the accident scene has been cleared. The very first problem was fixed relatively quickly, with a three-hour outage from October 19 at 11:48 PM until October 20 at 2:40 AM. However, as with the traffic jam example, dependencies started breaking, and didn't fully come online until much later.

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