diff --git a/releasenotes/notes/fix-fencing-action-parameter-8321d25a23d8ef99.yaml b/releasenotes/notes/fix-fencing-action-parameter-8321d25a23d8ef99.yaml
new file mode 100644
index 000000000..ff33a976b
--- /dev/null
+++ b/releasenotes/notes/fix-fencing-action-parameter-8321d25a23d8ef99.yaml
@@ -0,0 +1,8 @@
+---
+fixes:
+  - |
+    The `overcloud generate fencing` command no longer carries a default value
+    for the `action` parameter. Advice from upstream Pacemaker is that this
+    value should no longer be passed to fencing agents as it may cause
+    inconsistent behaviour. The parameter remains, but is now optional, and
+    its use is discouraged.
diff --git a/tripleoclient/tests/v1/test_overcloud_parameters.py b/tripleoclient/tests/v1/test_overcloud_parameters.py
index b8c52e381..fc459107a 100644
--- a/tripleoclient/tests/v1/test_overcloud_parameters.py
+++ b/tripleoclient/tests/v1/test_overcloud_parameters.py
@@ -145,7 +145,7 @@ class TestGenerateFencingParameters(utils.TestCommand):
         self.workflow.action_executions.create.assert_called_once_with(
             'tripleo.parameters.generate_fencing',
             {
-                'fence_action': 'reboot',
+                'fence_action': None,
                 'nodes_json': [
                     {
                         u'mac': [u'00:11:22:33:44:55'],
diff --git a/tripleoclient/v1/overcloud_parameters.py b/tripleoclient/v1/overcloud_parameters.py
index e083f3018..957d20a57 100644
--- a/tripleoclient/v1/overcloud_parameters.py
+++ b/tripleoclient/v1/overcloud_parameters.py
@@ -75,10 +75,10 @@ class GenerateFencingParameters(command.Command):
     def get_parser(self, prog_name):
         parser = super(GenerateFencingParameters, self).get_parser(prog_name)
         parser.add_argument('-a', '--action', dest='fence_action',
-                            default='reboot',
                             help=_('Operation to perform. Valid operations: '
                                    'on, off, reboot, status, list, diag, '
-                                   'monitor or metadata. Defaults to: reboot'))
+                                   'monitor or metadata. You should generally '
+                                   'not use this option.'))
         parser.add_argument('--delay', type=int,
                             help=_('Wait DELAY seconds before fencing is '
                                    'started'))