runc-examples VS qemu-user-static

EDIT: Looks like I don't need to `unshare` by hand but runc actually does this already:

https://github.com/psanford/runc-examples/blob/master/rootle...

and its "oh, you want multi-arch, do you?" friend. While prosecuting this <https://gitlab.com/gitlab-org/gitlab/-/issues/339567> I learned that https://hub.docker.com/layers/multiarch/qemu-user-static/7.2... actually mutates the binfmt_misc in buildx's context in order to exec the static copy of qemu in it https://github.com/multiarch/qemu-user-static/blob/v7.2.0-1/...

and, that the buildx plugin itself has some qemu magick in it, which got addressed in a minor version bump but I couldn't track down the relevant GitHub issue this second (I've flushed it from my mind, only recalling that there were a lot of actors in that tire fire)

deploy: <<: *build stage: deploy image: docker:20-cli script: - touch .env - export LOCAL_IMAGE="${CI_REGISTRY}/${CI_PROJECT_PATH}:${CI_COMMIT_TAG}" - wget https://github.com/multiarch/qemu-user-static/releases/download/v7.0.0-7/x86_64_qemu-aarch64-static.tar.gz - tar xzf x86_64_qemu-aarch64-static.tar.gz -C /usr/bin/ - docker buildx create --platform linux/arm64 --use - docker login -u gitlab-ci-token -p ${CI_JOB_TOKEN} ${CI_REGISTRY} - docker buildx build --platform linux/arm64 --tag ${LOCAL_IMAGE} --push . only: - tags ```

QEMU is a popular open-source emulator that can emulate a variety of CPU architectures, including ARM, PowerPC, and MIPS. multiarch/qemu-user-static is a Docker image that allows you to emulate different CPU architectures on your host machine using QEMU.

Next, you need to enable Qemu support for your Docker host instance. Qemu is a generic machine emulator and virtualiser. In simple terms, it allows your machine with one type of processor to emulate other types of processor, allowing your machine to execute scripts on different processor architectures.

Check out https://github.com/multiarch/qemu-user-static.

Another great tool for cross arch development is qemu-static-user. It allows you to run your nonnative architecture docker images on host using a qemu container for translation and only requires about one command to get working. It’s life saving for me when I need to test but setting up a full VM or native server is too time consuming.

https://github.com/multiarch/qemu-user-static

I'm just gonna leave these 2 here since I think they take a lot less effort to setup than the gcc-cross stuff and should be able to help you do stuff a lot faster: https://wiki.debian.org/QemuUserEmulation https://github.com/multiarch/qemu-user-static

multiarch/qemu-user-static is required for emulating ARM32 and Aarch64 instructions on x86_64 Linux.

This is MacOS's user mode x86 emulator ported to Linux. They intend for Linux VMs to use it as the interpreter for x86 binaries, including in containers. Basically a faster replacement for qemu-user-static .