this derivation will be built:
  /nix/store/v9gr9dqsjv95wxjmpkqpm2bj3cqiwasy-container-test-ubuntu-26-04-existing-files.drv
error: Cannot build '/nix/store/v9gr9dqsjv95wxjmpkqpm2bj3cqiwasy-container-test-ubuntu-26-04-existing-files.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/crr96cxmlh0waa3rshx250gbmxji7vaf-container-test-ubuntu-26-04-existing-files
       Last 25 log lines:
       > [ubuntu-26-04-existing-files] [  OK  ] Reached target getty.target - Login Prompts.
       > [ubuntu-26-04-existing-files] 
       > [ubuntu-26-04-existing-files]
       > [ubuntu-26-04-existing-files] Ubuntu 26.04.1 LTS ubuntu pts/0
       > [ubuntu-26-04-existing-files]
       > Traceback (most recent call last):
       >   File "/nix/store/dckppvyaygywla664igvsqpa1ngmq8h2-container-test-driver-0.0.1/bin/.container-test-driver-wrapped", line 9, in <module>
       >     sys.exit(main())
       >              ~~~~^^
       >   File "/nix/store/dckppvyaygywla664igvsqpa1ngmq8h2-container-test-driver-0.0.1/lib/python3.14/site-packages/test_driver/__init__.py", line 142, in main
       >     driver.run_tests()
       >     ~~~~~~~~~~~~~~~~^^
       >   File "/nix/store/dckppvyaygywla664igvsqpa1ngmq8h2-container-test-driver-0.0.1/lib/python3.14/site-packages/test_driver/driver.py", line 235, in run_tests
       >     self.test_script()
       >     ~~~~~~~~~~~~~~~~^^
       >   File "/nix/store/dckppvyaygywla664igvsqpa1ngmq8h2-container-test-driver-0.0.1/lib/python3.14/site-packages/test_driver/driver.py", line 231, in test_script
       >     exec(self.testscript, self.test_symbols(), None)
       >     ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
       >   File "<string>", line 1, in <module>
       >   File "/nix/store/dckppvyaygywla664igvsqpa1ngmq8h2-container-test-driver-0.0.1/lib/python3.14/site-packages/test_driver/driver.py", line 141, in start_all
       >     machine.wait_for_boot()
       >     ~~~~~~~~~~~~~~~~~~~~~^^
       >   File "/nix/store/dckppvyaygywla664igvsqpa1ngmq8h2-container-test-driver-0.0.1/lib/python3.14/site-packages/test_driver/machine.py", line 185, in wait_for_boot
       >     raise RuntimeError(msg)
       > RuntimeError: Timeout waiting for container ubuntu-26-04-existing-files to boot (last status: nsenter: cannot open /proc/54/ns/cgroup: No such file or directory)
       For full logs, run:
         nix log /nix/store/v9gr9dqsjv95wxjmpkqpm2bj3cqiwasy-container-test-ubuntu-26-04-existing-files.drv