59 lines
1.6 KiB
Bash
Executable file
59 lines
1.6 KiB
Bash
Executable file
#!/bin/bash
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# DinD: a wrapper script which allows docker to be run inside a docker container.
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# Original version by Jerome Petazzoni <jerome@dotcloud.com>
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# See the blog post: http://blog.docker.io/2013/09/docker-can-now-run-within-docker/
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#
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# This script should be executed inside a docker container in privilieged mode
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# ('docker run -privileged', introduced in docker 0.6).
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# Usage: dind CMD [ARG...]
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# First, make sure that cgroups are mounted correctly.
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CGROUP=/sys/fs/cgroup
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[ -d $CGROUP ] ||
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mkdir $CGROUP
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mountpoint -q $CGROUP ||
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mount -n -t tmpfs -o uid=0,gid=0,mode=0755 cgroup $CGROUP || {
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echo "Could not make a tmpfs mount. Did you use -privileged?"
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exit 1
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}
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# Mount the cgroup hierarchies exactly as they are in the parent system.
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for SUBSYS in $(cut -d: -f2 /proc/1/cgroup)
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do
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[ -d $CGROUP/$SUBSYS ] || mkdir $CGROUP/$SUBSYS
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mountpoint -q $CGROUP/$SUBSYS ||
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mount -n -t cgroup -o $SUBSYS cgroup $CGROUP/$SUBSYS
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done
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# Note: as I write those lines, the LXC userland tools cannot setup
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# a "sub-container" properly if the "devices" cgroup is not in its
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# own hierarchy. Let's detect this and issue a warning.
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grep -q :devices: /proc/1/cgroup ||
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echo "WARNING: the 'devices' cgroup should be in its own hierarchy."
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grep -qw devices /proc/1/cgroup ||
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echo "WARNING: it looks like the 'devices' cgroup is not mounted."
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# Now, close extraneous file descriptors.
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pushd /proc/self/fd
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for FD in *
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do
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case "$FD" in
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# Keep stdin/stdout/stderr
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[012])
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;;
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# Nuke everything else
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*)
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eval exec "$FD>&-"
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;;
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esac
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done
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popd
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# Mount /tmp
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mount -t tmpfs none /tmp
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exec $*
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