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[Launchpad Bug Tracker <1693361@xxxxxxxxxxxxxxxxxx>]

This bug was fixed in the package cloud-init - 0.7.9-153-g16a7302f-
0ubuntu1~16.04.2

---------------
cloud-init (0.7.9-153-g16a7302f-0ubuntu1~16.04.2) xenial-proposed; urgency=medium

  * debian/patches/ds-identify-behavior-xenial.patch: refresh patch.
  * cherry-pick 5fb49bac: azure: identify platform by well known value
    in chassis asset (LP: #1693939)
  * cherry-pick 003c6678: net: remove systemd link file writing from eni
    renderer
  * cherry-pick 1cd4323b: azure: remove accidental duplicate line in
    merge.
  * cherry-pick ebc9ecbc: Azure: Add network-config, Refactor net layer
    to handle duplicate macs. (LP: #1690430)
  * cherry-pick 11121fe4: systemd: make cloud-final.service run before
    apt daily (LP: #1693361)

 -- Scott Moser <smoser@xxxxxxxxxx>  Wed, 28 Jun 2017 17:17:18 -0400

** Changed in: cloud-init (Ubuntu Xenial)
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/1693361

Title:
  cloud-init sometimes fails on dpkg lock due to concurrent apt-
  daily.service execution

Status in APT:
  Confirmed
Status in cloud-init:
  Confirmed
Status in apt package in Ubuntu:
  New
Status in cloud-init package in Ubuntu:
  Fix Released
Status in cloud-init source package in Xenial:
  Fix Released
Status in cloud-init source package in Yakkety:
  Fix Committed
Status in cloud-init source package in Zesty:
  Fix Committed
Status in cloud-init source package in Artful:
  Fix Released

Bug description:
  === Begin SRU Template ===
  [Impact]
  A cloud-config that contains packages to install (see below) or
  'package_upgrade' will run 'apt-get update'.  That can sometimes fail as a
  result of contention with the apt-daily.service that updates that information.

  Cloud-config showing the problem is just like:

    $ cat my.yaml
    #cloud-config
    packages: ['hello']

  [Test Case]
  lxc-proposed-snapshot is
    https://git.launchpad.net/~smoser/cloud-init/+git/sru-info/tree/bin/lxc-proposed-snapshot
  It publishes an image to lxd with proposed enabled and cloud-init upgraded.

  a.) launch an instance with proposed version of cloud-init and some user-data.
     This is platform independent.  The test case demonstrates lxd.
     $ printf "%s\n%s\n%s\n" "#cloud-config" "packages: ['hello']" \
         "package_upgrade: true" > config.yaml
     $ release=xenial
     $ ref=proposed-$release
     $ ./lxc-proposed-snapshot --proposed --publish $release $ref;

  b.) start the instance
     $ name=$release-1693361
     $ lxc launch my-xenial "--config=user.user-data=$(cat config.yaml)
     $ sleep 1
     $ lxc exec $name -- tail -f /var/log/cloud-init.log /var/log/cloud-init-output.log
     # watch this boot.

   c.) Look for evidence of systemd failure
     journalctl -o short-precise | grep -i break
     journalctl -o short-precise | grep -i order

  [Regression Potential]
  Regression chance here is low.  Its possible that ordering loops
  could occur.  When that does happen, journalctl will mention it.  Unfortunately
  in such cases systemd somewhat randomly picks a service to kil so behavior
  is somewhat undefined.

  [Other Info]
  Upstream commit at
    https://git.launchpad.net/cloud-init/commit/?id=11121fe4

  === End SRU Template ===

  apt-daily is now a systemd service rather than being invoked by
  cron.daily.  If one builds a custom AMI it is possible that the apt-
  daily.timer will fire during boot.  This can fire at the same time
  cloud-init is running and if cloud-init loses the race the invocation
  of apt (e.g. use of "packages:" in the config) will fail.

  There is a lot of discussion online about this change to apt-daily
  (e.g. unattended upgrades happening during business hours, delaying
  boot, etc.) and discussion of potential systemd changes regarding
  timers firing during boot (c.f.
  https://github.com/systemd/systemd/issues/5659).

  While it would be better to solve this in apt itself, I suggest that
  cloud-init be defensive when calling apt and implement some retry
  mechanism.

  Various instances of people running into this issue:

  https://github.com/chef/bento/issues/609
  https://clusterhq.atlassian.net/browse/FLOC-4486
  https://github.com/boxcutter/ubuntu/issues/73
  https://unix.stackexchange.com/questions/315502/how-to-disable-apt-daily-service-on-ubuntu-cloud-vm-image

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