As a Developer I want to be able to build Windows Containers with BuildKit

[bplasmeijer]

The windows BuildKit is only supported on Linux

[jsturtevant]

It is possible to use buildx (which uses buildkit) if there are no RUN commands in the docker file:

docker buildx create --name img-builder --use
docker buildx build --no-cache --pull --push \
  --platform "windows/amd64" -t $imagetag -f $dockerfile .
docker buildx rm img-builder

ARG nanoserverTag="mcr.microsoft.com/windows/nanoserver:1809-amd64"
# othertags list: curl -L https://mcr.microsoft.com/v2/windows/nanoserver/tags/list

FROM ${nanoserverTag}
COPY some.exe "/Windows/System32/some.exe"

It would be interesting to see if could use some windows emulator connected to Binfmt_misc as QEMU is used for other architectures

[jorgearteiro]

There is an issue logged on BuildKit repo moby/buildkit#616

[TBBle]

@jsturtevant If you wanted to go down that path, I believe Wine can be used with binfmt_misc, although I'm not sure how well that would work with namespaces since there's a WineServer and configuration directory to create, and you probably don't want that in the final image...

It would be easier to prototype that on a raw Linux box than via the Linux support in Docker on Windows, I think.

This issue has been open for 30 days with no updates.
@immuzz, please provide an update or close this issue.

[TBBle]

Current status of my work on moby/buildkit#616 is that it's stalled waiting on a pile of 4 containerd PRs to be reviewed and advanced. The top of the stack is containerd/containerd#4419, but there's some outstanding design questions on the top two PRs regarding HCS behaviours, see microsoft/hcsshim#853, but the bottom two are just pending containerd maintainer review to merge or rework as appropriate.

And after that, will come fixing path-related issues in the BuildKit LLB layer, for which I'd only scratched the surface of in moby/buildkit#1621, exploring the solution space, and which needs to be reworked per maintainer feedback.

This issue has been open for 30 days with no updates.
@immuzz, please provide an update or close this issue.

[TBBle]

Status unchanged, still waiting on merging or feedback on containerd support for Windows container creation/export/mount support, and then continuing the work on BuildKit itself, starting from moby/buildkit#1621

[immuzz]

@kevpar Do you have any information on the containerd PRs mentioned above?

This issue has been open for 30 days with no updates.
@immuzz, please provide an update or close this issue.