fence_compute errors out with "Unable to establish connection to"

Issue

fence_compute errors out with Unable to establish connection to:

May 14 03:09:59 [46957] controller-0 stonith-ng:     info: update_remaining_timeout:  Attempted to execute agent fence_compute (status) the maximum number of times (2) allowed
May 14 03:09:59 [46957] controller-0 stonith-ng:   notice: status_search_cb:  Unknown result when testing if stonith-fence_compute-fence-nova can fence overcloud-compute-1: rc=-201
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [ Traceback (most recent call last): ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/sbin/fence_compute", line 512, in <module> ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     main() ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/sbin/fence_compute", line 488, in main ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     connection = create_nova_connection(options) ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/sbin/fence_compute", line 266, in create_nova_connection ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     keystone_versions = discover.available_versions(options["--auth-url"]) ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/lib/python2.7/site-packages/keystoneclient/discover.py", line 74, in available_versions ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     return _discover.get_version_data(session, url) ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/lib/python2.7/site-packages/keystoneclient/_discover.py", line 38, in get_version_data ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     resp = session.get(url, headers=headers, authenticated=authenticated) ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/lib/python2.7/site-packages/keystoneclient/session.py", line 535, in get ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     return self.request(url, 'GET', **kwargs) ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/lib/python2.7/site-packages/keystoneclient/session.py", line 428, in request ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     resp = send(**kwargs) ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [   File "/usr/lib/python2.7/site-packages/keystoneclient/session.py", line 472, in _send_request ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [     raise exceptions.ConnectionRefused(msg) ]
May 14 03:09:59 [46957] controller-0 stonith-ng:  warning: log_action:        fence_compute[674019] stderr: [ keystoneauth1.exceptions.connection.ConnectFailure: Unable to establish connection to https://X.X.X.X:13000 ]
May 14 03:09:59 [46957] controller-0 stonith-ng:     info: update_remaining_timeout:  Attempted to execute agent fence_compute (status) the maximum number of times (2) allowed
May 14 03:09:59 [46957] controller-0 stonith-ng:   notice: status_search_cb:  Unknown result when testing if stonith-fence_compute-fence-nova can fence overcloud-compute-1: rc=-201
May 14 03:10:03 [46955] controller-0        cib:     info: cib_process_ping:  Reporting our current digest to controller-2: 5b016fc8b5b938747ee40a184fe1f004 for 0.534.0 (0x55baa32fca70 0)
May 14 03:10:05 [46957] controller-0 stonith-ng:   notice: remote_op_done:    Operation reboot of overcloud-compute-1 by controller-2 for crmd.946003@controller-2.2b3b170f: Gene
ric Pacemaker error