moby/contrib/dockerize-disk.sh
Maxim Kulkin d1af2bc253 Add tool to conver disk image into Docker image
dockerize-image tool takes a virtual disk image file
and creates a Docker image based on it. You can
specify a base Docker image to make this tool create
an image that will contain only filesystem diff
instead of full filesystem.
See tools usage for details.

Signed-off-by: Maxim Kulkin <maxim.kulkin@gmail.com>
2015-03-27 14:53:54 -07:00

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#!/usr/bin/env bash
set -e
if ! command -v qemu-nbd &> /dev/null; then
echo >&2 'error: "qemu-nbd" not found!'
exit 1
fi
usage() {
echo "Convert disk image to docker image"
echo ""
echo "usage: $0 image-name disk-image-file [ base-image ]"
echo " ie: $0 cirros:0.3.3 cirros-0.3.3-x86_64-disk.img"
echo " $0 ubuntu:cloud ubuntu-14.04-server-cloudimg-amd64-disk1.img ubuntu:14.04"
}
if [ "$#" -lt 2 ]; then
usage
exit 1
fi
CURDIR=$(pwd)
image_name="${1%:*}"
image_tag="${1#*:}"
if [ "$image_tag" == "$1" ]; then
image_tag="latest"
fi
disk_image_file="$2"
docker_base_image="$3"
block_device=/dev/nbd0
builddir=$(mktemp -d)
cleanup() {
umount "$builddir/disk_image" || true
umount "$builddir/workdir" || true
qemu-nbd -d $block_device &> /dev/null || true
rm -rf $builddir
}
trap cleanup EXIT
# Mount disk image
modprobe nbd max_part=63
qemu-nbd -rc ${block_device} -P 1 "$disk_image_file"
mkdir "$builddir/disk_image"
mount -o ro ${block_device} "$builddir/disk_image"
mkdir "$builddir/workdir"
mkdir "$builddir/diff"
base_image_mounts=""
# Unpack base image
if [ -n "$docker_base_image" ]; then
mkdir -p "$builddir/base"
docker pull "$docker_base_image"
docker save "$docker_base_image" | tar -xC "$builddir/base"
image_id=$(docker inspect -f "{{.Id}}" "$docker_base_image")
while [ -n "$image_id" ]; do
mkdir -p "$builddir/base/$image_id/layer"
tar -xf "$builddir/base/$image_id/layer.tar" -C "$builddir/base/$image_id/layer"
base_image_mounts="${base_image_mounts}:$builddir/base/$image_id/layer=ro+wh"
image_id=$(docker inspect -f "{{.Parent}}" "$image_id")
done
fi
# Mount work directory
mount -t aufs -o "br=$builddir/diff=rw${base_image_mounts},dio,xino=/dev/shm/aufs.xino" none "$builddir/workdir"
# Update files
cd $builddir
diff -rq disk_image workdir \
| sed -re "s|Only in workdir(.*?): |DEL \1/|g;s|Only in disk_image(.*?): |ADD \1/|g;s|Files disk_image/(.+) and workdir/(.+) differ|UPDATE /\1|g" \
| while read action entry; do
case "$action" in
ADD|UPDATE)
cp -a "disk_image$entry" "workdir$entry"
;;
DEL)
rm -rf "workdir$entry"
;;
*)
echo "Error: unknown diff line: $action $entry" >&2
;;
esac
done
# Pack new image
new_image_id="$(for i in $(seq 1 32); do printf "%02x" $(($RANDOM % 256)); done)"
mkdir -p $builddir/result/$new_image_id
cd diff
tar -cf $builddir/result/$new_image_id/layer.tar *
echo "1.0" > $builddir/result/$new_image_id/VERSION
cat > $builddir/result/$new_image_id/json <<-EOS
{ "docker_version": "1.4.1"
, "id": "$new_image_id"
, "created": "$(date -u +%Y-%m-%dT%H:%M:%S.%NZ)"
EOS
if [ -n "$docker_base_image" ]; then
image_id=$(docker inspect -f "{{.Id}}" "$docker_base_image")
echo ", \"parent\": \"$image_id\"" >> $builddir/result/$new_image_id/json
fi
echo "}" >> $builddir/result/$new_image_id/json
echo "{\"$image_name\":{\"$image_tag\":\"$new_image_id\"}}" > $builddir/result/repositories
cd $builddir/result
# mkdir -p $CURDIR/$image_name
# cp -r * $CURDIR/$image_name
tar -c * | docker load