Point to known-issues if COU execution fails (canonical#383)

- added manila-ganesha workaround

Closes canonical#381

cou/cli.py

@@ -225,6 +225,10 @@ def entrypoint() -> None:
     except COUException as exc:
         progress_indicator.fail()
         logger.error(exc)
+        logger.error(
+            "See the known issues at https://canonical-charmed-openstack-upgrader.readthedocs-"
+            "hosted.com/en/stable/reference/known-issues/"
+        )
         sys.exit(1)
     except JujuError as exc:
         progress_indicator.fail()

docs/reference/known-issues.rst

@@ -6,5 +6,23 @@ Potential known upgrade bugs and non-standard procedures are listed in the OpenS
 
 - `Issues, charm procedures, and OpenStack upgrade notes`_
 
+Manila Ganesha
+--------------
+
+Certain versions of the manila-ganesha charm incorrectly report their workload version, which
+can lead to false positive COU errors resembling the following one:
+
+
+.. code:: bash
+
+    [WARNING] Not possible to find the charm manila-ganesha in the lookup
+    [ERROR] 'manila-ganesha' with workload version 17.1.0 has no compatible OpenStack release.
+
+See `bug 2060751`_ for details.
+
+If affected, refresh the manila-ganesha charm to its most recent version (within the same release
+channel) and re-run COU.
+
 .. LINKS:
 .. _Issues, charm procedures, and OpenStack upgrade notes: https://docs.openstack.org/charm-guide/latest/project/issues-and-procedures.html
+.. _bug 2060751: https://bugs.launchpad.net/charm-manila-ganesha/+bug/2060751