[Bug 1834875] Re: cloud-init growpart race with udev

[Dan Streetman]

> Issuing a second
> trigger will repeat this.
> IMO, that's a non-zero amount of time that slows the boot down, so I'd like
> to avoid that.

systemd-udev-trigger.serivce retriggers *everything* at boot (except in
an unprivileged container where it can't), so I'm not sure how much
added time we're talking about just for a single block device.  But
yeah, you need the kernel to send a uevent to udevd after the partition
table is ready for udevd to read, or udevd won't get the right partition
table info; whether you do some locking to try to block udevd from
reading it or just retrigger an event after it's ready.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1834875

Title:
  cloud-init growpart race with udev

Status in cloud-init:
  Incomplete
Status in cloud-utils:
  New
Status in linux-azure package in Ubuntu:
  New
Status in systemd package in Ubuntu:
  Incomplete

Bug description:
  On Azure, it happens regularly (20-30%), that cloud-init's growpart
  module fails to extend the partition to full size.

  Such as in this example:

  ========================================

  2019-06-28 12:24:18,666 - util.py[DEBUG]: Running command ['growpart', '--dry-run', '/dev/sda', '1'] with allowed return codes [0] (shell=False, capture=True)
  2019-06-28 12:24:19,157 - util.py[DEBUG]: Running command ['growpart', '/dev/sda', '1'] with allowed return codes [0] (shell=False, capture=True)
  2019-06-28 12:24:19,726 - util.py[DEBUG]: resize_devices took 1.075 seconds
  2019-06-28 12:24:19,726 - handlers.py[DEBUG]: finish: init-network/config-growpart: FAIL: running config-growpart with frequency always
  2019-06-28 12:24:19,727 - util.py[WARNING]: Running module growpart (<module 'cloudinit.config.cc_growpart' from '/usr/lib/python3/dist-packages/cloudinit/config/cc_growpart.py'>) failed
  2019-06-28 12:24:19,727 - util.py[DEBUG]: Running module growpart (<module 'cloudinit.config.cc_growpart' from '/usr/lib/python3/dist-packages/cloudinit/config/cc_growpart.py'>) failed
  Traceback (most recent call last):
    File "/usr/lib/python3/dist-packages/cloudinit/stages.py", line 812, in _run_modules
      freq=freq)
    File "/usr/lib/python3/dist-packages/cloudinit/cloud.py", line 54, in run
      return self._runners.run(name, functor, args, freq, clear_on_fail)
    File "/usr/lib/python3/dist-packages/cloudinit/helpers.py", line 187, in run
      results = functor(*args)
    File "/usr/lib/python3/dist-packages/cloudinit/config/cc_growpart.py", line 351, in handle
      func=resize_devices, args=(resizer, devices))
    File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 2521, in log_time
      ret = func(*args, **kwargs)
    File "/usr/lib/python3/dist-packages/cloudinit/config/cc_growpart.py", line 298, in resize_devices
      (old, new) = resizer.resize(disk, ptnum, blockdev)
    File "/usr/lib/python3/dist-packages/cloudinit/config/cc_growpart.py", line 159, in resize
      return (before, get_size(partdev))
    File "/usr/lib/python3/dist-packages/cloudinit/config/cc_growpart.py", line 198, in get_size
      fd = os.open(filename, os.O_RDONLY)
  FileNotFoundError: [Errno 2] No such file or directory: '/dev/disk/by-partuuid/a5f2b49f-abd6-427f-bbc4-ba5559235cf3'

  ========================================

  @rcj suggested this is a race with udev. This seems to only happen on
  Cosmic and later.

To manage notifications about this bug go to:
https://bugs.launchpad.net/cloud-init/+bug/1834875/+subscriptions