This is a beta release. Most things should work, but it's possible there are undiscovered issues in the release and we recommend continuing to use our stable v4.5.0 release for critical workloads. If you do spot any problems, we'd really appreciate it if you submit a GitHub issue or reply to our forum thread for this beta release where we will offer continued support.
What's new?
Previously experimental Lambda-based scaler is the new default 🚀
Our previously experimental fast autoscaler that scales up much faster is now always used. Instances will automatically scale to demand using the stack defaults and you should see good results without changing any parameters.
Experimental Windows support is now available 
A new AMI built on Windows Server 2019 is optionally available to use in the stack for Windows builds. You can enable this by changing the InstanceOperatingSystem setting from the default linux to windows. We've observed issues with Windows instances when MinSize is set above 0, so please avoid that for now. Huge thanks to @jeremiahsnapp and @tduffield for their contribution here!
Added
- Support for buildkite/image-builder which can enable you to customize AMIs based off the ones we ship #692 (keithduncan)
- Support for multiple security groups on instances #667 (jdub)
- AMI and Lambda Scaler support more regions: ap-east-1 (Hong Kong), me-south-1 (Bahrain), af-south-1 (Cape Town), eu-south-1 (Milan) #718 (JuanitoFatas)
- Support for loading BuildkiteAgentTokenPath from AWS Parameter Store #601 (jradtilbrook), #625 (jradtilbrook)
Changed
- Use EC2 LaunchTemplate instead of a LaunchConfiguration #589 (lox)
- InstanceType default is now
t3.large(wast2.nano) #699 (pda)
Dependencies updated
- Bump Buildkite Agent to v3.24.0 #726 (JuanitoFatas)
- Bump Buildkite Agent Scaler to v1.0.1 #724 (JuanitoFatas)
- Bump docker to v19.03.13 (linux) and v19.03.12 (windows) and docker-compose to v1.27.4 (linux, windows uses latest choco version) #719 (yob) #723 (JuanitoFatas)
And much, much more, we recommend you view the full changelog for this release.
Upgrading
Perform a CloudFormation stack update with the following URL:
https://s3.amazonaws.com/buildkite-aws-stack/v5.0.0-beta1/aws-stack.yml
If you want to launch a new stack, you can use this link (make sure not to use your production AWS account, create a new one for CI):