heroku/builder:24 has been released with multi-architecture and ARM support!

[joshwlewis]

We have just released our latest CNB Builder ,heroku/builder:24! It includes brand new support for ARM64 application builds!

Give it a try by building your app like this:

cd /path/to/application
pack build my-app --builder heroku/builder:24

New multi-architecture support

If you're using an ARM64 computer (such as an Apple Silicon Mac or an AWS Graviton instance), pack build my-app heroku/builder:24 will produce a linux/arm64 image. If you're using an AMD64 computer (such as an Intel Mac, most desktops and laptops, or an AWS EC2 instance), the same command will produce a linux/amd64 image.

You may also specify which architecture you wish to build with via the --platform tag, like this (pack version 0.34.0 or newer required):

pack build my-app --platform linux/arm64 --builder heroku/builder:24

Updated base image and reduced size

heroku/builder:24 is based on Heroku-24, which in turn is based on Ubuntu:24.04. Therefore, a large number of Ubuntu packages have been updated.

Additionally, we adjusted which Ubuntu packages are installed to reduce the image size:

• We removed some less frequently used packages (such as Bazaar, Mercurial and Ghostscript)
• We removed some tools that are typically only required during the build (such as GCC, Make, Git
  and system Python) from the run image, but left them in the build image.

[nickhammond]

Nice work on reducing the image size! The buildpack built image for one of my apps is only a few mbs bigger than the native Docker one which is great.