TL;DR

AWS’s October 19, 2025 outage— which dragged on for over 24 hours— boiled down to a cascading DNS failure. A misstep in DynamoDB’s DNS triggered errors in EC2, which then cascaded into Network Load Balancer failures. The official RCA is up on AWS’s website.

What You’ll Learn

• 0:00 – Quick summary

• 5:30 – How DynamoDB lost its DNS

• 13:41 – EC2 error chain

• 16:16 – Network Load Balancer misfires

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