upstart depends on inotify, and overlayfs does not support inotify.
That means that the following results in 'tgt' not running. tgt is simply
used here as an example of a service that installs an upstart job and
starts it on package install.
lxc-clone -s -B overlayfs -o source-precise-amd64 -n test1
lxc-start -n test1
..
apt-get install tgt
The change here is to modify /sbin/start inside the container so that when
something explicitly tries 'start', it results in an explicit call to
'initctl reload-configuration' so that upstart is aware of the newly
placed job.
Should overlayfs ever gain inotify support, this should still not cause
any harm.
Signed-off-by: Scott Moser <smo...@ubuntu.com>
diff --git a/hooks/ubuntu-cloud-prep b/hooks/ubuntu-cloud-prep
index 7985a73..5e0a999 100755
--- a/hooks/ubuntu-cloud-prep
+++ b/hooks/ubuntu-cloud-prep
@@ -12,6 +12,7 @@
## LXC_SRC_NAME: old container name
## LXC_ROOTFS_PATH: path or device on which the root fs is located
+set -f
VERBOSITY="0"
error() { echo "$@" 1>&2; }
@@ -34,9 +35,56 @@ Usage: ${0##*/} [options] root-dir
EOF
}
+write_patched_start() {
+ cat > "$1" <<"EOF"
+#!/bin/bash
+## This is a wrapper around upstart's /sbin/start to ensure that
+## calling 'start' on a job after writing it to /etc/init will function
+## correctly despite broken/missing support for inotify in overlayfs.
+##
+real() { exec -a /sbin/start "/sbin/start.real" "$@"; }
+
+# no args or not root
+[ $# -ne 0 -a "$UID" = "0" ] || real "$@"
+
+job=""
+# find first argument that doesn't start with '-' as 'job'
+for x in "$@"; do
+ [ "${x#-}" = "$x" ] && { job="$x"; break; }
+done
+
+# if job isn't there, no reason to check further
+[ -n "$job" ] && [ -f "/etc/init/$job.conf" ] || real "$@"
+
+# on Unknown, 'status' exits 1, and prints 'Unknown job' to stderr.
+out=$(status "$@" 2>&1)
+[ $? -eq 1 -a "${out#*nknown job}" != "$out" ] || real "$@"
+
+initctl reload-configuration >/dev/null 2>&1
+real "$@"
+EOF
+ chmod 755 "$1"
+}
+
+patch_start() {
+ # patch /sbin/start inside root_d to deal with lack of inotify
+ local root_d="$1"
+
+ # already patched
+ [ -f "$root_d/sbin/start.real" ] &&
+ { debug 1 "$root_d 'start' seems already patched"; return 1; }
+
+ debug 1 "patching /sbin/start in $root_d"
+ chroot "$root_d" dpkg-divert --local --rename \
+ --divert /sbin/start.real --add /sbin/start ||
+ { error "failed to patch /sbin/start for overlayfs"; return 1; }
+
+ write_patched_start "$root_d/sbin/start"
+}
+
prep() {
local short_opts="Chi:L:S:u:v"
- local
long_opts="auth-key:,cloud,help,hostid:,name:,nolocales:,userdata:,verbose"
+ local
long_opts="auth-key:,cloud,help,hostid:,name:,nolocales:,patch-start,userdata:,verbose"
local getopt_out getopt_ret
getopt_out=$(getopt --name "${0##*/}" \
--options "${short_opts}" --long "${long_opts}" -- "$@" 2>/dev/null) ||
@@ -49,6 +97,8 @@ prep() {
local cur="" next=""
local userdata="" hostid="" authkey="" locales=1 cloud=0 name=""
+ local patch_start=0
+
while [ $# -ne 0 ]; do
cur="$1"; next="$2";
case "$cur" in
@@ -57,6 +107,7 @@ prep() {
--name) name="$next";;
-i|--hostid) hostid="$next";;
-L|--nolocales) locales=0;;
+ --patch-start) patch_start=1;;
-S|--auth-key)
[ -f "$next" ] ||
{ error "--auth-key: '$next' not a file"; return 1; }
@@ -86,6 +137,9 @@ prep() {
error "${0##*}: usage failed, continuing with defaults"
fi
+ [ "$patch_start" -eq 0 ] || patch_start "$root_d" ||
+ { error "failed to patch start for overlayfs"; return 1; }
+
local seed_d=""
seed_d="$root_d/var/lib/cloud/seed/nocloud-net"
if [ $cloud -eq 1 ]; then
@@ -149,10 +203,13 @@ main() {
local _LXC_HOOK
if [ -n "$LXC_ROOTFS_MOUNT" -a "$3" = "clone" ]; then
_LXC_HOOK="clone"
- local name="$1"
+ local name="$1" pstart=""
shift 3
- debug 1 prep "--name=$name" "$LXC_ROOTFS_MOUNT" "$@"
- prep "--name=$name" "$LXC_ROOTFS_MOUNT" "$@"
+ # if mountpoint is overlayfs then add '--patch-start'
+ [ "${LXC_ROOTFS_PATH#overlayfs}" != "${LXC_ROOTFS_PATH}" ] &&
+ pstart="--patch-start"
+ debug 1 prep "--name=$name" $pstart "$LXC_ROOTFS_MOUNT" "$@"
+ prep "--name=$name" $pstart "$LXC_ROOTFS_MOUNT" "$@"
else
_LXC_HOOK=""
prep "$@"
------------------------------------------------------------------------------
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