How do I troubleshoot InsufficientInstanceCapacity errors when starting or launching an EC2 instance?

Last updated: 2021-07-13

I'm unable to start or launch my Amazon Elastic Compute Cloud (Amazon EC2) instance, and I'm receiving an insufficient capacity error. How can I troubleshoot this issue and be sure that I have enough capacity for my critical machines?

Short description

If AWS doesn't currently have enough available On-Demand capacity to complete your request, you'll receive the following InsufficientInstanceCapacity error:

"An error occurred (InsufficientInstanceCapacity) when calling the RunInstances operation (reached max retries: 4). We currently do not have sufficient capacity in the Availability Zone you requested."


If you receive this error, do the following:

To avoid insufficient capacity errors on critical machines, consider using On-Demand Capacity Reservations. To use an On-Demand Capacity Reservation, do the following:

  1. Create the Capacity Reservation in an Availability Zone.
  2. Launch critical instances into your Capacity Reservation. You can view real-time Capacity Reservation usage, and launch instances into it as needed.

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