haproxy[1387]: proxy nova_compute_api_cluster has no server available!

I want to restart the `nova` related services: [root@ha-node1 nova]# systemctl restart openstack-nova-api.service openstack-nova-cert.service openstack-nova-consoleauth.service openstack-nova-scheduler.service openstack-nova-conductor.service openstack-nova-novncproxy.service But can not start the below red or yellow status node services:  The print out is below: [root@ha-node1 nova]# systemctl restart openstack-nova-api.service openstack-nova-cert.service openstack-nova-consoleauth.service openstack-nova-scheduler.service openstack-nova-conductor.service openstack-nova-novncproxy.service [root@ha-node1 nova]# Message from syslogd@localhost at Aug 5 01:02:14 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:03:17 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:04:22 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:05:23 ... haproxy[1387]: proxy nova-metadata-api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:06:15 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:06:38 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:06:59 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:07:39 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:09:01 ... haproxy[1387]: proxy nova_compute_api_cluster has no server available! Message from syslogd@localhost at Aug 5 01:09:46 ... haproxy[1387]: proxy nova-metadata-api_cluster has no server available!