CodeBuild Concurrency

CodeBuild Concurrency Limits

Amazon Web Services (AWS) CodeBuild is the build platform Flightcontrol uses for the Nixpacks and Dockerfile build types. AWS has recently set the concurrent build quota for many customers to 1 build at a time. This is problematic if you are building for multiple services.

This guide will show you how to increase the number of concurrent builds in AWS CodeBuild to avoid throttling.

There are no additional costs associated with increasing the number of concurrent builds, as you are only charged for the time your builds are running.

The error during the build process will be similar to the following:

"Failed to start build. Error: Cannot have more than 1 builds in queue for the account."


If you do see the above error, you need to request an increase from AWS for the following environments:

  • Linux/Small (used for static builds before Nov 2023)
  • Linux/Medium (used for web service and worker builds before Nov 2023)
  • Linux/Large (used for all service types build after Nov 2023)

We suggest asking for an increase to 10 build servers for each environment. If you have five or more Web Server or Worker services with Flightcontrol, or you and your team use preview environments heavily, you may want consider asking for an increase to 20 build servers for each environment.

If you increased the instance size of your CodeBuild build servers, you would need to request an increase for the new size (not typical for most Flightcontrol users).

AWS Quota Request screen for CodeBuild

A quota increase request does take time to process on the AWS side.