I tried to hack a bit with the rolebinding using the following commands (the CTX_CLUSTER2 environment variable points to the cluster with the model that consumes the secret).

kubectl --context="${CTX_CLUSTER2}" create namespace dev1

kubectl --context="${CTX_CLUSTER2}" create clusterrole holder --verb get,list --resource secret --resource namespace

kubectl --context="${CTX_CLUSTER2}" create rolebinding holder -n dev1 --serviceaccount dev:holder --clusterrole holder


But still got some errors related to the secret not being found.

unit-holder-0: 10:34:43 ERROR unit.holder/0.juju-log secret_id:10: Uncaught exception while in charm code:
Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2564, in _run
    result = run(args, **kwargs)
  File "/usr/lib/python3.8/subprocess.py", line 516, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '('/var/lib/juju/tools/unit-holder-0/secret-get', 'secret://548fc04a-1364-4f8f-875c-f9f39c7bed38/clu5bqurg8jc758htov0', '--format=json')' returned non-zero exit status 1.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2920, in secret_get
    result = self._run('secret-get', *args, return_output=True, use_json=True)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2570, in _run
    raise ModelError(e.stderr)
ops.model.ModelError: ERROR secret "clu5bqurg8jc758htov0-1" not found


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 282, in get_secret
    content = self._backend.secret_get(id=id, label=label)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2923, in secret_get
    raise SecretNotFoundError() from e
ops.model.SecretNotFoundError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2564, in _run
    result = run(args, **kwargs)
  File "/usr/lib/python3.8/subprocess.py", line 516, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '('/var/lib/juju/tools/unit-holder-0/secret-info-get', 'secret://548fc04a-1364-4f8f-875c-f9f39c7bed38/clu5bqurg8jc758htov0', '--format=json')' returned non-zero exit status 1.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2930, in _run_for_secret
    return self._run(*args, return_output=return_output, use_json=use_json)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2570, in _run
    raise ModelError(e.stderr)
ops.model.ModelError: ERROR secret "clu5bqurg8jc758htov0" not found


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "./src/charm.py", line 83, in <module>
    main(ConsumerCharm)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/main.py", line 435, in main
    _emit_charm_event(charm, dispatcher.event_name)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/main.py", line 144, in _emit_charm_event
    event_to_emit.emit(*args, **kwargs)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/framework.py", line 355, in emit
    framework._emit(event)  # noqa
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/framework.py", line 824, in _emit
    self._reemit(event_path)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/framework.py", line 899, in _reemit
    custom_handler(event)
  File "./src/charm.py", line 62, in _on_update_status
    secret = self._obtain_secret()
  File "./src/charm.py", line 35, in _obtain_secret
    return self.model.get_secret(id=secret_id)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 287, in get_secret
    info = self._backend.secret_info_get(id=id, label=label)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2944, in secret_info_get
    result = self._run_for_secret('secret-info-get', *args, return_output=True, use_json=True)
  File "/var/lib/juju/agents/unit-holder-0/charm/venv/ops/model.py", line 2933, in _run_for_secret
    raise SecretNotFoundError() from e
ops.model.SecretNotFoundError
unit-holder-0: 10:34:43 ERROR juju.worker.uniter.operation hook "secret_id-relation-changed" (via hook dispatching script: dispatch) failed: exit status 1

The output of `juju secrets` in each model is the following:

aks:dev1:
juju secrets
ID                    Owner           Rotation  Revision  Last updated
clu5bqurg8jc758htov0  owner1/0        never            1  1 minute ago


gke:dev (no secrets)
juju secrets
ID                    Owner           Rotation  Revision  Last updated