[Bug 2137175] [NEW] curtin crashes if os-release contains hashmarks

[Alan Baghumian]

Public bug reported:

While working on updating support for SLES16 in packer-maas I came
across this trace during deployments:

2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]: Stdout: start: cmd-install/stage-curthooks/builtin/cmd-curthooks: curtin command curthooks
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         running /tmp/tmpxsvc5qnw/target/curtin/curtin-hooks
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Running command ['/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks'] with allowed return codes [0] (capture=False)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Traceback (most recent call last):
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks", line 94, in <module>
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             main()
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks", line 89, in main
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             curthook(config, target, state)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks", line 45, in curthook
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             distro_info = distro.get_distroinfo(target=target)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/distro.py", line 119, in get_distroinfo
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             variant_os_release = os_release(target=target)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/distro.py", line 80, in os_release
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             data = load_shell_content(load_file(os_release),
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 1310, in load_shell_content
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             key, value = line.split("=", 1)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         ValueError: not enough values to unpack (expected 2, got 1)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         finish: cmd-install/stage-curthooks/builtin/cmd-curthooks: FAIL: curtin command curthooks
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Traceback (most recent call last):
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/commands/main.py", line 202, in main
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             ret = args.func(args)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/commands/curthooks.py", line 1915, in curthooks
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             if util.run_hook_if_exists(target, 'curtin-hooks'):
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 984, in run_hook_if_exists
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             subp([target_hook])
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 280, in subp
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             return _subp(*args, **kwargs)
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 144, in _subp
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             raise ProcessExecutionError(stdout=out, stderr=err,
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         curtin.util.ProcessExecutionError: Unexpected error while running command.
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Command: ['/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks']
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Exit code: 1
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Reason: -
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stdout: ''
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stderr: ''
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Unexpected error while running command.
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Command: ['/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks']
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Exit code: 1
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Reason: -
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stdout: ''
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stderr: ''
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:
2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]: Stderr: ''

Looking deeper this was caused by the presence of some comment lines in
SLES16's /etc/os-release file. I worked around the issue by applying a
custom curtin hook to address this during the custom image build,
however this needs to get addressed both in curtin and MAAS which uses a
custom curtin branch.


Steps to reproduce: Try to deploy an image that has an /etc/os-release file containing lines starting with # sign.


Expected behavior (what should have happened?): curtin should have ignored the comment lines and not crashed.


Actual behavior (what actually happened?): curtin crashes leading to a
failed deployment with the above trace.


MAAS version and installation type (deb, snap): This was reproduced in a
MAAS 3.4.7 lab, however it is not directly MAAS related. The latest
curtin code branch still has this issue.

** Affects: curtin
     Importance: Undecided
         Status: New

** Affects: maas
     Importance: Undecided
         Status: New

** Also affects: curtin
   Importance: Undecided
       Status: New

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https://bugs.launchpad.net/bugs/2137175

Title:
  curtin crashes if os-release contains hashmarks

Status in curtin:
  New
Status in MAAS:
  New

Bug description:
  While working on updating support for SLES16 in packer-maas I came
  across this trace during deployments:

  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]: Stdout: start: cmd-install/stage-curthooks/builtin/cmd-curthooks: curtin command curthooks
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         running /tmp/tmpxsvc5qnw/target/curtin/curtin-hooks
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Running command ['/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks'] with allowed return codes [0] (capture=False)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Traceback (most recent call last):
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks", line 94, in <module>
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             main()
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks", line 89, in main
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             curthook(config, target, state)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks", line 45, in curthook
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             distro_info = distro.get_distroinfo(target=target)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/distro.py", line 119, in get_distroinfo
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             variant_os_release = os_release(target=target)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/distro.py", line 80, in os_release
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             data = load_shell_content(load_file(os_release),
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 1310, in load_shell_content
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             key, value = line.split("=", 1)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         ValueError: not enough values to unpack (expected 2, got 1)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         finish: cmd-install/stage-curthooks/builtin/cmd-curthooks: FAIL: curtin command curthooks
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Traceback (most recent call last):
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/commands/main.py", line 202, in main
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             ret = args.func(args)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/commands/curthooks.py", line 1915, in curthooks
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             if util.run_hook_if_exists(target, 'curtin-hooks'):
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 984, in run_hook_if_exists
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             subp([target_hook])
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 280, in subp
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             return _subp(*args, **kwargs)
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:           File "/curtin/curtin/util.py", line 144, in _subp
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:             raise ProcessExecutionError(stdout=out, stderr=err,
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         curtin.util.ProcessExecutionError: Unexpected error while running command.
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Command: ['/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks']
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Exit code: 1
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Reason: -
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stdout: ''
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stderr: ''
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Unexpected error while running command.
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Command: ['/tmp/tmpxsvc5qnw/target/curtin/curtin-hooks']
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Exit code: 1
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Reason: -
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stdout: ''
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:         Stderr: ''
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]:
  2025-12-12T18:14:47-08:00 small-4 cloud-init[1782]: Stderr: ''

  Looking deeper this was caused by the presence of some comment lines
  in SLES16's /etc/os-release file. I worked around the issue by
  applying a custom curtin hook to address this during the custom image
  build, however this needs to get addressed both in curtin and MAAS
  which uses a custom curtin branch.

  
  Steps to reproduce: Try to deploy an image that has an /etc/os-release file containing lines starting with # sign.

  
  Expected behavior (what should have happened?): curtin should have ignored the comment lines and not crashed.


  Actual behavior (what actually happened?): curtin crashes leading to a
  failed deployment with the above trace.


  MAAS version and installation type (deb, snap): This was reproduced in
  a MAAS 3.4.7 lab, however it is not directly MAAS related. The latest
  curtin code branch still has this issue.

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