Charms enters `Error` state when deployed on its own: lightkube.core.exceptions.LoadResourceError: No module named 'lightkube.resources.metacontroller_v1alpha1'

[mvlassis]

Bug Description

The resource -dispatcher charm enters an Error state when deployed on its own, with this error message from the debug logs:

lightkube.core.exceptions.LoadResourceError: No module named 'lightkube.resources.metacontroller_v1alpha1'. If using a CRD, ensure you define a generic resource.

The issue seems to be that some CRDs are missing that are usually applied with the metacontroller-operator charm.

To Reproduce

• Get a fresh microk8s installation
• Deploy the resource-dispatcher charm with juju deploy resource-dispatcher --trust
• The charm should enter an Error state after some time

Environment

Charm channel: latest/stable
Juju: 3.4.5
Microk8s: 1.29

Relevant Log Output

unit-resource-dispatcher-0: 12:58:51 ERROR unit.resource-dispatcher/0.juju-log Uncaught exception while in charm code:
Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/lightkube/codecs.py", line 37, in _load_model
    module = importlib.import_module(f'lightkube.resources.{version.lower()}')
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'lightkube.resources.metacontroller_v1alpha1'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./src/charm.py", line 296, in <module>
    main(ResourceDispatcherOperator)
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/ops/main.py", line 441, in main
    _emit_charm_event(charm, dispatcher.event_name)
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/ops/main.py", line 149, in _emit_charm_event
    event_to_emit.emit(*args, **kwargs)
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/ops/framework.py", line 344, in emit
    framework._emit(event)
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/ops/framework.py", line 841, in _emit
    self._reemit(event_path)
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/ops/framework.py", line 930, in _reemit
    custom_handler(event)
  File "./src/charm.py", line 141, in _on_install
    self._deploy_k8s_resources()
  File "./src/charm.py", line 131, in _deploy_k8s_resources
    self.k8s_resource_handler.apply()
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/charmed_kubeflow_chisme/kubernetes/_kubernetes_resource_handler.py", line 324, in apply
    resources = self.render_manifests(force_recompute=False)
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/charmed_kubeflow_chisme/kubernetes/_kubernetes_resource_handler.py", line 272, in render_manifests
    self._manifests = codecs.load_all_yaml(
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/lightkube/codecs.py", line 105, in load_all_yaml
    return _flatten(yaml.safe_load_all(stream))
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/lightkube/codecs.py", line 98, in _flatten
    res = from_dict(obj)
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/lightkube/codecs.py", line 61, in from_dict
    model = _load_model(d['apiVersion'], d['kind'])
  File "/var/lib/juju/agents/unit-resource-dispatcher-0/charm/venv/lightkube/codecs.py", line 40, in _load_model
    raise LoadResourceError(f"{e}. If using a CRD, ensure you define a generic resource.")
lightkube.core.exceptions.LoadResourceError: No module named 'lightkube.resources.metacontroller_v1alpha1'. If using a CRD, ensure you define a generic resource.
unit-resource-dispatcher-0: 12:58:51 ERROR juju.worker.uniter.operation hook "install" (via hook dispatching script: dispatch) failed: exit status 1

Additional Context

We should probably handle the CRD missing and put the charm into a Blocked state.

[syncronize-issues-to-jira]

Thank you for reporting us your feedback!

The internal ticket has been created: https://warthogs.atlassian.net/browse/KF-6282.

This message was autogenerated

[mvlassis]

After discussing about this with the team:

• We consider this a bug, and the charm should ideally stay in a Blocked state until the CRD is applied.
• A simple fix would be to add an if statement checking for the CRD, and stay in a Blocked state if it isn't present.
• As a better solution, we have decided adding a relation between resource-dispatcher and admission-webhook to track whether the CRD is applied.