| #!/bin/bash |
| |
| # DinD: a wrapper script which allows docker to be run inside a docker container. |
| # Original version by Jerome Petazzoni <jerome@dotcloud.com> |
| # See the blog post: http://blog.docker.io/2013/09/docker-can-now-run-within-docker/ |
| # |
| # This script should be executed inside a docker container in privilieged mode |
| # ('docker run -privileged', introduced in docker 0.6). |
| |
| # Usage: dind CMD [ARG...] |
| |
| # First, make sure that cgroups are mounted correctly. |
| CGROUP=/sys/fs/cgroup |
| |
| [ -d $CGROUP ] || |
| mkdir $CGROUP |
| |
| mountpoint -q $CGROUP || |
| mount -n -t tmpfs -o uid=0,gid=0,mode=0755 cgroup $CGROUP || { |
| echo "Could not make a tmpfs mount. Did you use -privileged?" |
| exit 1 |
| } |
| |
| if [ -d /sys/kernel/security ] && ! mountpoint -q /sys/kernel/security |
| then |
| mount -t securityfs none /sys/kernel/security || { |
| echo "Could not mount /sys/kernel/security." |
| echo "AppArmor detection and -privileged mode might break." |
| } |
| fi |
| |
| # Mount the cgroup hierarchies exactly as they are in the parent system. |
| for SUBSYS in $(cut -d: -f2 /proc/1/cgroup) |
| do |
| [ -d $CGROUP/$SUBSYS ] || mkdir $CGROUP/$SUBSYS |
| mountpoint -q $CGROUP/$SUBSYS || |
| mount -n -t cgroup -o $SUBSYS cgroup $CGROUP/$SUBSYS |
| |
| # The two following sections address a bug which manifests itself |
| # by a cryptic "lxc-start: no ns_cgroup option specified" when |
| # trying to start containers withina container. |
| # The bug seems to appear when the cgroup hierarchies are not |
| # mounted on the exact same directories in the host, and in the |
| # container. |
| |
| # Named, control-less cgroups are mounted with "-o name=foo" |
| # (and appear as such under /proc/<pid>/cgroup) but are usually |
| # mounted on a directory named "foo" (without the "name=" prefix). |
| # Systemd and OpenRC (and possibly others) both create such a |
| # cgroup. To avoid the aforementioned bug, we symlink "foo" to |
| # "name=foo". This shouldn't have any adverse effect. |
| echo $SUBSYS | grep -q ^name= && { |
| NAME=$(echo $SUBSYS | sed s/^name=//) |
| ln -s $SUBSYS $CGROUP/$NAME |
| } |
| |
| # Likewise, on at least one system, it has been reported that |
| # systemd would mount the CPU and CPU accounting controllers |
| # (respectively "cpu" and "cpuacct") with "-o cpuacct,cpu" |
| # but on a directory called "cpu,cpuacct" (note the inversion |
| # in the order of the groups). This tries to work around it. |
| [ $SUBSYS = cpuacct,cpu ] && ln -s $SUBSYS $CGROUP/cpu,cpuacct |
| done |
| |
| # Note: as I write those lines, the LXC userland tools cannot setup |
| # a "sub-container" properly if the "devices" cgroup is not in its |
| # own hierarchy. Let's detect this and issue a warning. |
| grep -q :devices: /proc/1/cgroup || |
| echo "WARNING: the 'devices' cgroup should be in its own hierarchy." |
| grep -qw devices /proc/1/cgroup || |
| echo "WARNING: it looks like the 'devices' cgroup is not mounted." |
| |
| # Now, close extraneous file descriptors. |
| pushd /proc/self/fd >/dev/null |
| for FD in * |
| do |
| case "$FD" in |
| # Keep stdin/stdout/stderr |
| [012]) |
| ;; |
| # Nuke everything else |
| *) |
| eval exec "$FD>&-" |
| ;; |
| esac |
| done |
| popd >/dev/null |
| |
| # Mount /tmp |
| mount -t tmpfs none /tmp |
| |
| [ "$1" ] && exec "$@" |
| echo "You probably want to run hack/make.sh, or maybe a shell?" |