Add info to find if OpenSearch is broken

Author: MoteHue

doc/source/operations/upgrading.rst

@@ -122,8 +122,17 @@ Known issues
 
 * If you run ``kayobe overcloud service upgrade`` twice, it will cause shard
   allocation to be disabled in OpenSearch. See `LP#2049512
-  <https://bugs.launchpad.net/kolla-ansible/+bug/2049512>`__ for details. For
-  now, the easiest way to fix this is to turn allocation back on:
+  <https://bugs.launchpad.net/kolla-ansible/+bug/2049512>`__ for details.
+
+  You can check if this is affecting your system with the following command. If
+  ``transient.cluster.routing.allocation.enable=none`` is present, shard
+  allocation is disabled.
+
+  .. code-block:: console
+
+      curl http://<controller-ip>:9200/_cluster/settings
+
+  For now, the easiest way to fix this is to turn allocation back on:
 
    .. code-block:: console