Re: [Qemu-devel] [PATCH RFC v4 4/4] docker: Add debootstrap-arm image

["Alex Bennée" <alex.bennee@linaro.org>]

Fam Zheng <famz@redhat.com> writes:

> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  tests/docker/dockerfiles/debootstrap-arm.docker | 35 +++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>  create mode 100644 tests/docker/dockerfiles/debootstrap-arm.docker
>
> diff --git a/tests/docker/dockerfiles/debootstrap-arm.docker b/tests/docker/dockerfiles/debootstrap-arm.docker
> new file mode 100644
> index 0000000..cb15f2f
> --- /dev/null
> +++ b/tests/docker/dockerfiles/debootstrap-arm.docker
> @@ -0,0 +1,35 @@
> +FROM debian:testing
> +
> +RUN apt-get update
> +RUN apt-get install -y fakeroot debootstrap qemu-user-static
> +
> +RUN mkdir /debootstrap-arm
> +
> +RUN cd /debootstrap-arm && fakeroot debootstrap --variant=buildd --foreign \
> +    --arch=armhf testing . http://httpredir.debian.org/debian
> +
> +RUN sed -i 's/in_target mount/echo not for docker in_target mount/g' \
> +    /debootstrap-arm/debootstrap/functions
> +
> +RUN mkdir -p /debootstrap-arm/usr/local/bin
> +
> +RUN ln /usr/bin/qemu-arm-static /debootstrap-arm/usr/bin/qemu-arm && \
> +    ln /usr/bin/qemu-arm-static /debootstrap-arm/usr/bin/qemu-arm-static && \
> +    ln /usr/bin/qemu-arm-static /debootstrap-arm/usr/local/bin/qemu-arm && \
> +    ln /usr/bin/qemu-arm-static /debootstrap-arm/usr/local/bin/qemu-arm-static
> +
> +# Run stage 2
> +RUN if ! chroot /debootstrap-arm /debootstrap/debootstrap --second-stage; then \
> +        echo "Failed to chroot and do stage 2"; \
> +        echo "Please set up binfmt_misc to point arm binary to one of:"; \
> +        echo "  /usr/bin/qemu-arm"; \
> +        echo "  /usr/bin/qemu-arm-static"; \
> +        echo "  /usr/local/bin/qemu-arm"; \
> +        echo "  /usr/local/bin/qemu-arm-static"; \
> +        exit 1; \
> +    fi
> +RUN chroot /debootstrap-arm sh -c 'cat /etc/apt/sources.list | sed "s/deb/deb-src/" >> /etc/apt/sources.list'
> +RUN chroot /debootstrap-arm apt-get update
> +RUN chroot /debootstrap-arm apt-get build-dep -y qemu
> +RUN chroot /debootstrap-arm apt-get install -y ccache
> +ENV QEMU_CHROOT /debootstrap-arm

OK I've done some more experimenting and two things are apparent:

  debootstrap is widely packaged for various distros

And

  The script it fairly portable so we can always run it directly

I hacked up the .pre script to do the following and tested on my Arch
VM:

#!/bin/sh
#
# Simple wrapper for debootstrap, run in the docker build context
#
FAKEROOT=`which fakeroot 2> /dev/null`
DEBOOTSTRAP=`which debootstrap 2> /dev/null`
DEBOOTSTRAP_SOURCE=https://anonscm.debian.org/git/d-i/debootstrap.git

if [ -z $FAKEROOT ]; then
    echo "Please install fakeroot to enable bootstraping"
    exit 1
fi

if [ -z $DEBOOTSTRAP ]; then
    echo "No debootstrap installed, attempting to install from SCM"
    git clone ${DEBOOTSTRAP_SOURCE} ./debootstrap.git
    export DEBOOTSTRAP_DIR=./debootstrap.git
    DEBOOTSTRAP=./debootstrap.git/debootstrap
fi

echo "Building a rootfs using ${FAKEROOT} and ${DEBOOTSTRAP}"

${FAKEROOT} /bin/sh -x ${DEBOOTSTRAP} --variant=buildd --foreign --arch=$DEB_ARCH $DEB_TYPE . http://httpredir.debian.org/debian
exit 0

So I think it is feasible to but the pre-requisite checking and work
around in the pre script and be done with it. It seems neater than the
chroot within a container approach.

Thoughts?

--
Alex Bennée