[Bug 1987663] Re: cinder-volume: "Failed to re-export volume, setting to ERROR" with "tgtadm: failed to send request hdr to tgt daemon, Transport endpoint is not connected" on service startup

[Timo Aaltonen]

Hello Mauricio, or anyone else affected,

Accepted cinder into mantic-proposed. The package will build now and be
available at
https://launchpad.net/ubuntu/+source/cinder/2:23.0.0-0ubuntu1.2 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-
mantic to verification-done-mantic. If it does not fix the bug for you,
please add a comment stating that, and change the tag to verification-
failed-mantic. 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: cinder (Ubuntu Mantic)
       Status: In Progress => Fix Committed

** Tags added: verification-needed verification-needed-mantic

** Changed in: cinder (Ubuntu Jammy)
       Status: In Progress => Fix Committed

** Tags added: verification-needed-jammy

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https://bugs.launchpad.net/bugs/1987663

Title:
  cinder-volume: "Failed to re-export volume, setting to ERROR" with
  "tgtadm: failed to send request hdr to tgt daemon, Transport endpoint
  is not connected" on service startup

Status in Ubuntu Cloud Archive:
  Fix Released
Status in Ubuntu Cloud Archive antelope series:
  Triaged
Status in Ubuntu Cloud Archive bobcat series:
  In Progress
Status in Ubuntu Cloud Archive caracal series:
  Fix Released
Status in Ubuntu Cloud Archive ussuri series:
  Triaged
Status in Ubuntu Cloud Archive victoria series:
  Won't Fix
Status in Ubuntu Cloud Archive wallaby series:
  Won't Fix
Status in Ubuntu Cloud Archive xena series:
  Won't Fix
Status in Ubuntu Cloud Archive yoga series:
  In Progress
Status in Ubuntu Cloud Archive zed series:
  Won't Fix
Status in cinder package in Ubuntu:
  Fix Released
Status in cinder source package in Bionic:
  Won't Fix
Status in cinder source package in Focal:
  Fix Committed
Status in cinder source package in Jammy:
  Fix Committed
Status in cinder source package in Lunar:
  Won't Fix
Status in cinder source package in Mantic:
  Fix Committed
Status in cinder source package in Noble:
  Fix Released

Bug description:
  [Impact]

   * The cinder-volume service might fail to re-export volumes
     in-use on startup if tgt.service isn't fully started yet.

   * This affects the 'lvm' driver with 'tgtadm' target helper
     (which runs 'tgtadm' commands that need the service ready).

   * Snippets from /var/log/cinder/cinder-volume.log:

     Failed to re-export volume, setting to ERROR.
     ...
     Command: tgtadm --lld iscsi --op show --mode target
     ...
     Stderr: 'tgtadm: failed to send request hdr to tgt daemon,
     Transport endpoint is not connected\n'

   * This issue is more common in openstack compute nodes
     with networking (ovs/ovn) that takes long to startup,
     which might delay the startup of tgt.service _after_
     cinder-volume.service.

  [Test Steps]

   * Steps to reproduce are detailed in comment #3.
     Summary:

   * Install mysql, rabbitmq-server, keystone, and cinder
     (controller and storage nodes; backup node unneeded).

   * Configure cinder-volume (storage node) for LVM backend
     and tgtadm iSCSI helper (tgt.service).

   * Create a cinder volume, and configure it as 'in-use'.

   * Simulate a start delay on tgt.service with a drop-in.

   * Restart services: cinder-volume.service tgt.service

   * Check sequence of service startup.

   * Check status of the cinder volume:
     'in-use' (expected) or 'error' (bug).

   * Check log file /var/log/cinder/cinder-volume.log for
     'tgtadm: failed to send request hdr to tgt daemon'.

  [Regression Potential]

   * The fix introduces systemd unit 'After=' and 'Wants='
     properties for tgt.service in cinder-volume.service,
     thus might delay the boot process (multi-user.target).

       $ systemctl show cinder-volume.service | grep WantedBy=
       WantedBy=multi-user.target

   * However, the boot process already waits on tgt.service
     anyway, thus the difference (if any) should not be big,
     and would provide more correct behavior.

       $ systemctl show tgt.service | grep WantedBy=
       WantedBy=multi-user.target

   * If tgt.service is not present (tgt package not installed)
     _no errors_ occur, as both 'After=' and 'Wants=' are weak
     ordering/dependency properties (man 5 systemd.unit).

  [Other Info]

   * The fix uses a systemd service drop-in snippet because
     the service unit is generated by openstack-pkg-tools
     (pkgos-gen-systemd-unit) based on the 'init' service,
     and it only emits 'Wants=' for network-online.target.

   * Changing that in openstack-pkg-tools changes behavior
     in stable releases, and only manifest at build time,
     for many openstack packages that have no issues now.

   * We'll continue to pursue the general improvement in
     Debian, so it comes into Ubuntu development release,
     but for the Ubuntu stable releases, this should do.

  [Original Bug Description]

  Real-world example in comment #2.

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