We have now restored power to all instances and network devices within the affected data center and are seeing recovery for the majority of EC2 instances and EBS volumes within the affected Availability Zone. Network connectivity within the affected Availability Zone has also returned to normal levels.

We are investigating increased EC2 launch failures and networking connectivity issues for some instances in a single Availability Zone (USE1-AZ4) in the US-EAST-1 Region. Other Availability Zones within the US-EAST-1 Region are not affected by this issue.

This is affecting availability and connectivity to EC2 instances that are part of the affected data center within the affected Availability Zone. We are also experiencing elevated RunInstance API error rates for launches within the affected Availability Zone.

We’ll update this post as we learn more about the situation.