@@ -13,16 +13,79 @@ set -e

 # apparmor sucks and Docker needs to know that it's in a container (c) @tianon

 export container=docker

-# First, make sure that cgroups are mounted correctly.

-CGROUP=/cgroup

+# as of docker 1.8, cgroups will be mounted in the container

+if ! mountpoint -q /sys/fs/cgroup; then

-mkdir -p "$CGROUP"

+	# First, make sure that cgroups are mounted correctly.

+	CGROUP=/cgroup

-if ! mountpoint -q "$CGROUP"; then

-	mount -n -t tmpfs -o uid=0,gid=0,mode=0755 cgroup $CGROUP || {

-		echo >&2 'Could not make a tmpfs mount. Did you use --privileged?'

-		exit 1

-	}

+	mkdir -p "$CGROUP"

+

+	if ! mountpoint -q "$CGROUP"; then

+		mount -n -t tmpfs -o uid=0,gid=0,mode=0755 cgroup $CGROUP || {

+			echo >&2 'Could not make a tmpfs mount. Did you use --privileged?'

+			exit 1

+		}

+	fi

+

+	# Mount the cgroup hierarchies exactly as they are in the parent system.

+	for HIER in $(cut -d: -f2 /proc/1/cgroup); do

+

+		# The following sections address a bug which manifests itself

+		# by a cryptic "lxc-start: no ns_cgroup option specified" when

+		# trying to start containers within a 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.

+

+		SUBSYSTEMS="${HIER%name=*}"

+

+		# If cgroup hierarchy is named(mounted with "-o name=foo") we

+		# need to mount it in $CGROUP/foo to create exect same

+		# directoryes as on host. Else we need to mount it as is e.g.

+		# "subsys1,subsys2" if it has two subsystems

+

+		# 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. So just mount them on directory $CGROUP/foo.

+

+		OHIER=$HIER

+		HIER="${HIER#*name=}"

+

+		mkdir -p "$CGROUP/$HIER"

+

+		if ! mountpoint -q "$CGROUP/$HIER"; then

+			mount -n -t cgroup -o "$OHIER" cgroup "$CGROUP/$HIER"

+		fi

+

+		# 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.

+

+		if [ "$HIER" = 'cpuacct,cpu' ]; then

+			ln -s "$HIER" "$CGROUP/cpu,cpuacct"

+		fi

+

+		# If hierarchy has multiple subsystems, in /proc/<pid>/cgroup

+		# we will see ":subsys1,subsys2,subsys3,name=foo:" substring,

+		# we need to mount it to "$CGROUP/foo" and if there were no

+		# name to "$CGROUP/subsys1,subsys2,subsys3", so we must create

+		# symlinks for docker daemon to find these subsystems:

+		# ln -s $CGROUP/foo $CGROUP/subsys1

+		# ln -s $CGROUP/subsys1,subsys2,subsys3 $CGROUP/subsys1

+

+		if [ "$SUBSYSTEMS" != "${SUBSYSTEMS//,/ }" ]; then

+			SUBSYSTEMS="${SUBSYSTEMS//,/ }"

+			for SUBSYS in $SUBSYSTEMS

+			do

+				ln -s "$CGROUP/$HIER" "$CGROUP/$SUBSYS"

+			done

+		fi

+	done

 fi

 if [ -d /sys/kernel/security ] && ! mountpoint -q /sys/kernel/security; then

@@ -32,65 +95,6 @@ if [ -d /sys/kernel/security ] && ! mountpoint -q /sys/kernel/security; then

 	}

 fi

-# Mount the cgroup hierarchies exactly as they are in the parent system.

-for HIER in $(cut -d: -f2 /proc/1/cgroup); do

-

-	# The following sections address a bug which manifests itself

-	# by a cryptic "lxc-start: no ns_cgroup option specified" when

-	# trying to start containers within a 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.

-

-	SUBSYSTEMS="${HIER%name=*}"

-

-	# If cgroup hierarchy is named(mounted with "-o name=foo") we

-	# need to mount it in $CGROUP/foo to create exect same

-	# directoryes as on host. Else we need to mount it as is e.g.

-	# "subsys1,subsys2" if it has two subsystems

-

-	# 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. So just mount them on directory $CGROUP/foo.

-

-	OHIER=$HIER

-	HIER="${HIER#*name=}"

-

-	mkdir -p "$CGROUP/$HIER"

-

-	if ! mountpoint -q "$CGROUP/$HIER"; then

-		mount -n -t cgroup -o "$OHIER" cgroup "$CGROUP/$HIER"

-	fi

-

-	# 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.

-

-	if [ "$HIER" = 'cpuacct,cpu' ]; then

-		ln -s "$HIER" "$CGROUP/cpu,cpuacct"

-	fi

-

-	# If hierarchy has multiple subsystems, in /proc/<pid>/cgroup

-	# we will see ":subsys1,subsys2,subsys3,name=foo:" substring,

-	# we need to mount it to "$CGROUP/foo" and if there were no

-	# name to "$CGROUP/subsys1,subsys2,subsys3", so we must create

-	# symlinks for docker daemon to find these subsystems:

-	# ln -s $CGROUP/foo $CGROUP/subsys1

-	# ln -s $CGROUP/subsys1,subsys2,subsys3 $CGROUP/subsys1

-

-	if [ "$SUBSYSTEMS" != "${SUBSYSTEMS//,/ }" ]; then

-		SUBSYSTEMS="${SUBSYSTEMS//,/ }"

-		for SUBSYS in $SUBSYSTEMS

-		do

-			ln -s "$CGROUP/$HIER" "$CGROUP/$SUBSYS"

-		done

-	fi

-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.