It would be a surprise if the build tools make a difference.

I tried stable and master branch.

unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   ERROR: Command errored out with exit status 1:
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm    command: /var/lib/juju/agents/unit-ovn-chassis-0/.venv/bin/python /var/lib/juju/agents/unit-ovn-chassis-0/.venv/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-9t364s9x/overlay --no-warn-script-location --no-binary :none: --only-binary :none: --no-index --find-links wheelhouse -- 'setuptools>=56' 'setuptools_scm[toml]>=3.4.1'
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm        cwd: None
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   Complete output (3 lines):
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   Looking in links: wheelhouse
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   ERROR: Could not find a version that satisfies the requirement setuptools>=56 (from versions: 41.6.0)
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   ERROR: No matching distribution found for setuptools>=56
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   ----------------------------------------
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm ERROR: Command errored out with exit status 1: /var/lib/juju/agents/unit-ovn-chassis-0/.venv/bin/python /var/lib/juju/agents/unit-ovn-chassis-0/.venv/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-9t364s9x/overlay --no-warn-script-location --no-binary :none: --only-binary :none: --no-index --find-links wheelhouse -- 'setuptools>=56' 'setuptools_scm[toml]>=3.4.1' Check the logs for full command output.
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm Traceback (most recent call last):
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   File "/var/lib/juju/agents/unit-ovn-chassis-0/charm/hooks/upgrade-charm", line 8, in <module>
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm     basic.bootstrap_charm_deps()
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   File "/var/lib/juju/agents/unit-ovn-chassis-0/charm/lib/charms/layer/basic.py", line 224, in bootstrap_charm_deps
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm     check_call([pip, 'install', '-U', reinstall_flag, '--no-index',
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm   File "/usr/lib/python3.8/subprocess.py", line 364, in check_call
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm     raise CalledProcessError(retcode, cmd)
unit-ovn-chassis-0: 18:39:46 WARNING unit.ovn-chassis/0.upgrade-charm subprocess.CalledProcessError: Command '['/var/lib/juju/agents/unit-ovn-chassis-0/.venv/bin/pip', 'install', '-U', '--force-reinstall', '--no-index', '--no-cache-dir', '-f', 'wheelhouse', 'dnspython==1.16.0', 'importlib-metadata==4.8.3', 'netaddr==0.7.19', 'attrs==22.1.0', 'netifaces==0.11.0', 'pbr==5.10.0', 'PyYAML==5.3.1', 'charms.reactive==1.5.0', 'six==1.16.0', 'charmhelpers==1.1.1.dev37', 'jsonschema==3.2.0', 'pyrsistent==0.18.0', 'Jinja2==3.0.3', 'pyaml==21.10.1', 'psutil==5.9.1', 'charms.openstack==0.0.1.dev1', 'zipp==3.6.0', 'typing-extensions==4.1.1']' returned non-zero exit status 1.
unit-ovn-chassis-0: 18:39:46 ERROR juju.worker.uniter.operation hook "upgrade-charm" (via explicit, bespoke hook script) failed: exit status 1
unit-ovn-chassis-0: 18:39:46 INFO juju.worker.uniter awaiting error resolution for "upgrade-charm" hook




tailed output

root@juju-c9096a-28:/var/lib/juju/agents/unit-ovn-chassis-0/charm# '/var/lib/juju/agents/unit-ovn-chassis-0/.venv/bin/pip' 'install' '-U' '--force-reinstall' '--no-index' '--no-cache-dir' '-f' 'wheelhouse' 'charms.openstack==0.0.1.dev1' 'dnspython==1.16.0' 'jsonschema==3.2.0' 'pyrsistent==0.18.0' 'Jinja2==3.0.3' 'PyYAML==5.3.1' 'charms.reactive==1.5.0' 'zipp==3.6.0' 'netaddr==0.7.19' 'pbr==5.10.0' 'pyaml==21.10.1' 'attrs==22.1.0' 'six==1.16.0' 'netifaces==0.11.0' 'typing-extensions==4.1.1' 'importlib-metadata==4.8.3' 'psutil==5.9.1' 'charmhelpers==1.1.1.dev37'
Looking in links: wheelhouse
Processing ./wheelhouse/charms.openstack-0.0.1.dev1.zip
Processing ./wheelhouse/dnspython-1.16.0.zip
Processing ./wheelhouse/jsonschema-3.2.0.tar.gz
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Installing backend dependencies ... done
    Preparing wheel metadata ... done
Processing ./wheelhouse/pyrsistent-0.18.0.tar.gz
  Installing build dependencies ... error
  ERROR: Command errored out with exit status 1:
   command: /var/lib/juju/agents/unit-ovn-chassis-0/.venv/bin/python /var/lib/juju/agents/unit-ovn-chassis-0/.venv/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-0e4xgmxo/overlay --no-warn-script-location --no-binary :none: --only-binary :none: --no-index --find-links wheelhouse -- 'setuptools>=42' wheel
       cwd: None
  Complete output (3 lines):
  Looking in links: wheelhouse
  ERROR: Could not find a version that satisfies the requirement setuptools>=42 (from versions: 41.6.0)
  ERROR: No matching distribution found for setuptools>=42
  ----------------------------------------
ERROR: Command errored out with exit status 1: /var/lib/juju/agents/unit-ovn-chassis-0/.venv/bin/python /var/lib/juju/agents/unit-ovn-chassis-0/.venv/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-0e4xgmxo/overlay --no-warn-script-location --no-binary :none: --only-binary :none: --no-index --find-links wheelhouse -- 'setuptools>=42' wheel Check the logs for full command output.



Anyway. I will re-try on Monday. I already had a Friday afternoon white whine schorle. :D
Thanks for your help so far.