cgroup u/mounting

cgroup.sh

#!/bin/bash

set -eu

function ensureMounted() {
  source=$1
  shift
  target=$1
  shift
  type=$1
  shift
  opts=${1:-}

  mkdir -p "$target"

  if grep -q "${target} " /proc/self/mounts; then
    return 0
  fi

  cmd="mount -t $type $source $target"
  if [ -n "${opts:-}" ]; then
    cmd="$cmd -o $opts"
  fi
  $cmd
}

function ensureUnmounted() {
  point=$1
  shift
  if grep -q "${point} " /proc/self/mounts; then
    umount "$point"
  fi
}

cgroot=/sys/fs/cgroup

if [ "${1:-}" == "destroy" ]; then
  ensureUnmounted /cgroups
  ensureUnmounted $cgroot/devices
  ensureUnmounted $cgroot/cpuset
  ensureUnmounted $cgroot/cpu
  ensureUnmounted $cgroot/memory
  ensureUnmounted $cgroot
  exit 0
fi

ensureMounted none $cgroot tmpfs
ensureMounted cgroup /cgroups cgroup cpu,memory # this will cause runc to break
ensureMounted cgroup $cgroot/devices cgroup devices
ensureMounted cgroup $cgroot/cpuset cgroup cpuset
ensureMounted cgroup $cgroot/cpu cgroup cpu,memory
ensureMounted cgroup $cgroot/memory cgroup cpu,memory