Request limit exceeded - ec2:DescribeVolumes

Question

Hello everyone,

I'm getting the error:
"Failed to describe volume vol-00e99999999969d0
Request limit exceeded. Account 999999999 has been throttled on ec2:DescribeVolumes."

This error occurs both through the console and the API/CLI. Even Elastic Beanstalk is receiving this error when trying to add a new EC2 to its Scaling.

Using AWS Cli query on CloudTrail to list requests made this month with AttributeValue=DescribeVolumes, only 13 results were returned.

How can I find out what's consuming my rate limit? This is directly impacting our application's scalability.

Thank you in advance.

re:Post Agent · Answer

AWS throttles Amazon EC2 API requests for each AWS account on a per-Region basis to help maintain service performance. The error you're seeing indicates that your account has exceeded the maximum allowed API request rate for the DescribeVolumes operation.

Even though your CloudTrail query only shows 13 results, there are several possible explanations for why you're experiencing throttling:

1. CloudTrail might not be capturing all API calls, especially if they're being made programmatically at high frequency.

2. The throttling could be caused by automated processes or applications making frequent DescribeVolumes calls. This could include monitoring tools, custom scripts, or third-party applications that query volume information.

3. For large clusters or environments that scale drastically, EC2 API requests around provisioning can encounter request throttling. DescribeVolumes is specifically listed as one of the read-only actions that commonly experiences throttling.

4. Unpaginated requests for DescribeVolumes are particularly susceptible to throttling and timeouts. AWS strongly recommends using only paginated requests when working with this API.

To address this issue:

1. Implement pagination in your API calls to DescribeVolumes.

2. Reduce the frequency of your API calls by implementing caching strategies.

3. Monitor your API usage with CloudWatch metrics in the AWS/EC2/API namespace. Look for the RequestLimitExceeded metric to track throttling events.

4. Consider reaching out to AWS Support to request an increase in your API rate limits if needed for your workload.

The throttling is affecting both your console access and programmatic access because all API calls (whether from applications, CLI, or the console) count toward the same rate limit for your AWS account.  
**Sources**  
[Troubleshooting API request errors - Amazon Elastic Compute Cloud](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/query-api-troubleshooting.html)  
[DescribeVolumes - Amazon Elastic Compute Cloud](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeVolumes.html)  
[Known Limits and Service Quotas - Amazon EKS](https://docs.aws.amazon.com/eks/latest/best-practices/known_limits_and_service_quotas.html)  
[Monitor Amazon EC2 API requests using Amazon CloudWatch - Amazon Elastic Compute Cloud](https://docs.aws.amazon.com/ec2/latest/devguide/monitor.html)

Request limit exceeded - ec2:DescribeVolumes

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