Docker Cli legacy build deprecated on windows with no replacement available
Nobody has claimed this yet.
Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 35/100
- Issue type
- Bug
- Clarity
- Mostly clear
- Activity status
- Quiet
- Tech stack
- docker, github-actions, go
- Domain
- build-system, ci-cd, cli, operating-systems
Research direction
Start with the Docker CLI build entry point and reproduce the legacy-builder deprecation on a GitHub Actions Windows runner using the runner image information linked in the issue. Compare the behavior for Windows containers with Buildx and BuildKit, then verify whether the warning or fallback is appropriate. Done means Windows builds have a supported, reproducible path without the reported deprecation failure.
Written by the indexing model from the issue text.
Description
Description
When attempting to build windows docker images from windows github runners, the docker cli reports an error that the legacy builder is deprecated.
DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
Install the buildx component to build images with BuildKit:
https://docs.docker.com/go/buildx/
The problem is that buildx and buildkit do not work well on windows, and any support for them is still experimental.
Either this warning is being incorrectly applied when attempting to build windows containers, or this deprecation is happening before windows containers can be supported by the newer build systems.
See https://github.com/open-telemetry/opentelemetry-dotnet-instrumentation/pull/4876 for an attempt to enable buildx and buildkit on a github windows runner and a link to an example job that failed with the legacy builder deprecation message.
Reproduce
- Setup a github actions job to run on a windows runner
- Use the docker cli to build a windows container.
- Sometimes it will successfully, and other times it fails with the deprecation message.
Expected behavior
Either the windows docker containers should continue to built using the legacy builder, or the newer build system needs to fully support windows containers.
docker version
N/A
docker info
N/A
Additional Info
See https://github.com/actions/runner-images/blob/main/images/windows/Windows2025-Readme.md for the information about which docker tools (and their versions) are installed on windows runners.
- Dominant language
- Go
- Stars
- 6.1k
- Forks
- 2.2k
- Avg merge
- 1d 15h
- Merged PRs (30d)
- 43
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
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