A Visual Breakdown of the AWS US-EAST-1 Disruption of October 20th
Total Disruption Duration
15h 12m
From initial impact to full service recovery.
The outage wasn't a single event, but a chain reaction that rippled through core AWS infrastructure, starting with a fundamental service failure.
The initial trigger. DNS, the internet's phone book, failed for DynamoDB endpoints, making the critical database service unreachable.
With DynamoDB unstable, a dependent internal subsystem for launching new EC2 instances began to fail, creating a compute bottleneck.
The EC2 issues then impaired the system monitoring Network Load Balancer health, causing widespread network connectivity problems.
11:49 PM (Oct 19)
Initial impact begins with increased error rates and latencies.
2:24 AM
DynamoDB DNS issue resolved. Services begin recovery, but EC2 impairment is discovered.
9:38 AM
Network Load Balancer health checks are recovered, a major step in restoring connectivity.
3:01 PM
Full Recovery. All AWS services return to normal operations, though some backlogs persist.
The outage was centered in the **US-EAST-1 (N. Virginia)** region, but its impact was global. This is because US-EAST-1 is AWS's oldest and largest region, and it hosts the control planes for many global services like IAM.
When US-EAST-1 failed, it wasn't just applications in that region that broke; management and administrative functions for services worldwide were also affected, demonstrating the risk of a centralized dependency.
The outage directly hit a wide range of foundational services.
This outage highlighted the critical need for resilient architecture. Companies can adopt several strategies to protect themselves from similar regional failures.
The mandatory baseline. Distribute applications across multiple Availability Zones within one region to survive data-center-level failures.
Maintain a standby or active architecture in a separate AWS Region. Use services like Route 53 for automatic failover.
Use services like SQS and Lambda to create loosely coupled systems where a failure in one component doesn't cascade to others.
For critical data, leverage services with built-in cross-region replication like DynamoDB Global Tables or Aurora Global Database.
For maximum resilience, store critical backups and recovery plans in a different cloud provider or on-premises for a true "escape hatch".
Continuously test failover procedures to ensure they work as expected. An untested disaster recovery plan is not a plan.