Merge lp:~smoser/maas-images/trunk.disable-kernel-hooks into lp:maas-images

[Scott Moser]

stop grub scripts from running when upgrading an image.

An upgrade that brought a new kernel would cause grub's' kernel
hook scripts to run. Those would fail to run and cause failure
(at least in trusty). This is similar to code that is currently
in the kpack-from-image, but handles putting things back more elegantly.
(kpack-from-image doesn't have to put things back).

I found this when running with '--proposed'.

[lp:~smoser/maas-images/trunk.disable-kernel-hooks]

388. By Scott Moser on 2018-01-17

cleanup a bit and add debug

389. By Scott Moser on 2018-01-17

check taht it exists.

[Lee Trager (ltrager)]

LGTM!

review: Approve

=== modified file 'bin/maas-cloudimg2ephemeral'
--- bin/maas-cloudimg2ephemeral	2017-05-05 15:19:06 +0000
+++ bin/maas-cloudimg2ephemeral	2018-01-17 20:00:58 +0000
@@ -42,6 +42,7 @@
 
 VERBOSITY=0
 TOP_D="${0%/*}"
+DISABLE_SUFFIX=".eph-temp-disabled"
 command -v unshare-pidns >/dev/null 2>&1 || PATH="${0%/*}:$PATH"
 
 error() { echo "$@" 1>&2; }
@@ -88,11 +89,34 @@
 EOF
     [ $? -eq 0 ] && chmod 755 "$dir/usr/sbin/policy-rc.d" ||
         { error "failed to write policy-rc.d"; return 1; }
+
+    ( set -e;
+      cd "$dir"
+      for f in ./etc/kernel/*.d/*-grub; do
+           [ -x "$f" ] || continue
+           abs=${f#.}
+           debug 2 "Disabling $abs via dpkg-divert rename"
+           chroot "$dir" dpkg-divert --local --rename --divert \
+               "${abs}${DISABLE_SUFFIX}" "${abs}"
+      done
+    )
 }
 
 undisable_services() {
     local dir="$1"
     rm -f "$dir/usr/sbin/policy-rc.d"
+
+    ( set -e;
+      cd "$dir"
+      for f in ./etc/kernel/*.d/*${DISABLE_SUFFIX}; do
+           [ -e "$f" ] || continue
+           abs=${f#.}
+           orig=${abs%${DISABLE_SUFFIX}}
+           debug 2 "Re-enabling $orig via dpkg-divert removal."
+           chroot "$dir" dpkg-divert --local --remove --rename --divert \
+               "${abs}" "${orig}"
+      done
+    )
 }
 
 check_required_vars() {