Duplicate buildkit daemon processes with multi-app deployments

[jefvlamings]

When building with Docker (via Kamal) a daemon process buildkitd is spawned. buildkitd is the daemon that runs in the background to handle the build processes. It is responsible for executing build tasks, managing caching, and optimizing the build process. E.g.:

docker buildx build --push --platform linux/arm64 --builder kamal-service-native-remote

The builder tag kamal-service-native-remote is constructed with the name of the service that you've defined in your deploy.yml.

Problem

When you're building multiple different apps on the same build server, you will get a buildkitd for each application. The more apps you have running, the more redundant buildkitd process that keep running. Keep in mind that a buildkitd process takes up a 100's of megabytes.

As far is I understand we could reuse the same daemon process for different application builds. Remotely or locally, this will save up precious RAM.

Solution

Do we need the service name to be part of the builder name in --builder? If so, would it be an option to override it in deploy.yml like:

builder:
  remote:
    arch: arm64
    host: xxx.xxx.xxx.xxx
    name: default

Which would result in

docker buildx build --push --platform linux/arm64 --builder kamal-default-native-remote