Architecture: x86_64 vs arm64

By default, Jets deploys Lambda functions that use the arm64 architecture. This is because it’s cheaper and faster. It can up to a whopping 40%.

If you need to use the x86_64 architecture instead, this page shows you how.


You just need to configure the CodeBuild remote runner to use the x86_64 architecture.


Jets.bootstrap.configure do
  config.codebuild.project.environment = {
    ComputeType: "BUILD_GENERAL1_MEDIUM",
    Image: "aws/codebuild/amazonlinux2-x86_64-standard:5.0",

That’s enough because Jets detects the host machine architecture and configures Lambda functions, builds gem, and Dockefile, etc appropriately.

Important: If you are using a Docker Host to speed up your builds, the Docker Host will determine the Docker image architecture, not just the CodeBuild remote runner. Your custom Docker Host architecture must match the CodeBuild remote runner architecture.

Switching Architecture

Interestingly, you can switch between x86_64 and arm64 architecture and do an in-place deploy, IE: A blue-green deploy is not required. Only changing the Lambda Function Package Type requires a blue-green deployment.

CodeBuild and Docker Host Arch Must Match

The CodeBuild Remote Runner and Docker Host architectures must match. Otherwise, the deployment when using the Zip Package Type will not work. Jets creates the final zip artifact on the CodeBuild Remote Runner. Hence, both need to match.

This only applies if you provide your own custom Docker Host, which helps speed up the deployment.

Local Machine Architecture

Your local machine architecture, in general, will not matter to the final deployment architecture. This is because Jets deploys mainly with the CodeBuild Remote Runner, which controls the architecture.