sts-sponsors team mailing list archive

[Steve Langasek <1930203@xxxxxxxxxxxxxxxxxx>]

Hello reemguin, or anyone else affected,

Accepted tang into focal-proposed. The package will build now and be
available at https://launchpad.net/ubuntu/+source/tang/7-1ubuntu0.1 in a
few hours, and then in the -proposed repository.

Please help us by testing this new package.  See
https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how
to enable and use -proposed.  Your feedback will aid us getting this
update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug,
mentioning the version of the package you tested, what testing has been
performed on the package and change the tag from verification-needed-
focal to verification-done-focal. If it does not fix the bug for you,
please add a comment stating that, and change the tag to verification-
failed-focal. In either case, without details of your testing we will
not be able to proceed.

Further information regarding the verification process can be found at
https://wiki.ubuntu.com/QATeam/PerformingSRUVerification .  Thank you in
advance for helping!

N.B. The updated package will be released to -updates after the bug(s)
fixed by this package have been verified and the package has been in
-proposed for a minimum of 7 days.

** Changed in: tang (Ubuntu Focal)
       Status: In Progress => Fix Committed

** Tags added: verification-needed verification-needed-focal

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https://bugs.launchpad.net/bugs/1930203

Title:
  ordering cycle after reboot

Status in tang package in Ubuntu:
  Fix Released
Status in tang source package in Focal:
  Fix Committed

Bug description:
  [ Impact ]
  The enabled tangd.socket service starting on boot is unreliable, due to
  the start job being deleted as a result of a systemd ordering cycle.
  Users relying on tangd to be started on boot have to manually
  check that the service started after a reboot, or implement custom
  workarounds to ensure the same.

  The fix removes the opportunity for an ordering cycle to occur in the
  unit by moving dependencies out of the socket unit and changing the
  WantedBy to sockets.target (what it should be for a socket unit).

  [ Test Plan ]
  The bug is reproduced by installing 'tang' (version 7-1build1) on a machine running Focal 20.04.6 or earlier. The unit should be enabled by default.
   `sudo apt install tang`

  After installing the package, ensure the tang service is enabled.
   `systemctl is-enabled tang`

  reboot the server, and check that the tangd.socket service is running
   `systemctl status tangd.socket`

  The service may or may not be running depending how systemd ordered
  the startup jobs for this boot. You can simply repeat rebooting the server
  and eventually at some point the service will not come up after a boot.

  Regardless if the service is started on boot, you can see similar messages
  to these in the system log:
  Apr  5 05:01:05 tangtest-vm-2 kernel: systemd[1]: sockets.target: Found ordering cycle on tangd.socket/start
  Apr  5 05:01:05 tangtest-vm-2 kernel: systemd[1]: sockets.target: Found dependency on tangd-update.service/start
  Apr  5 05:01:05 tangtest-vm-2 kernel: systemd[1]: sockets.target: Found dependency on basic.target/start
  Apr  5 05:01:05 tangtest-vm-2 kernel: systemd[1]: sockets.target: Found dependency on sockets.target/start
  Apr  5 05:01:05 tangtest-vm-2 kernel: systemd[1]: sockets.target: Job tangd.socket/start deleted to break ordering cycle starting with sockets.target/start

  The fix requires modifying the tangd.socket unit WantedBy from multi-
  user.target to sockets.target. This means the 'enabled' status relies
  on links in a different directory before and after upgrade. The
  upgrade ought to remove the old multi-user.target link. So assuming
  the unit is 'enabled', the only links existing should be:

  Before upgrade:
  /etc/systemd/system/multi-user.target.wants/tangd.socket

  After upgrade:
  /etc/systemd/system/sockets.target.wants/tangd.socket

  [ Where problems could occur ]
  The tang service may not start correctly. If it is made to be part of
  a systemd dependency chain with other services, those services may also
  be impacted/fail to start.

  Since the systemd units are altered, even if the service starts it may
  change the way the tang service was originally configured to run. Other
  applications/clients relying on the tang service may experiences issues
  if the service is not running as originally configured in prior release.

  [ Other Info ]
  The proposed fix is derived from an upstream fix:
  https://github.com/latchset/tang/commit/77785125fb56

  There is a minor modification to the diff since the Ubuntu package
  source file for tangd.socket has a '.in' extension, upstream does not.

  Versions starting with v8 already contain the fix:
  $ git describe --contains 77785125fb56
  v8~9

  Since we are updating the WantedBy link from multi-user to socket via
  a change in postinst, a downgrade using `apt install tang={version}`
  will not have a postinst to account for this. The best way to
  downgrade is to remove the package, and then install the desired
  version to add the correct link.

  Original bug text below:
  ----------
  I had the same issue, described here: https://bugzilla.redhat.com/show_bug.cgi?id=1792173
  This issue was found, because tangd didn't provide the advertisement payload anymore, after reboot.

  Ubuntu version: 20.04.2
  Package version of tang: 7-1build1

  The bug could be fixed by the recommended changes from Renaud Métrich 2020-01-17 08:35:08 UTC.
  ----------

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