OpenStack : Nova Error : NoValidHost

Problem:

On Controller node , File /var/log/nova/nova-conductor.log

2015-10-23 18:20:30.836 1572 ERROR nova.scheduler.utils [req-20b92c63-df02-4c16-941e-5b7c0b68aa96 b476579221d74f1eb0474fb5d970dead eec1d66ee98a46458c98f2c84607c229 - - -] [instance: d39eb1ab-14f8-4bc7-8029-3c5fb92cdf95] Error from last host: fedora-68 (node fedora-68): [u'Traceback (most recent call last):\n', u'  File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 2235, in _do_build_and_run_instance\n    filter_properties)\n', u'  File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 2381, in _build_and_run_instance\n    instance_uuid=instance.uuid, reason=six.text_type(e))\n', u"RescheduledException: Build of instance d39eb1ab-14f8-4bc7-8029-3c5fb92cdf95 was re-scheduled: Connection to glance host IP:9292 failed: Error finding address for http://IP:9292/v1/images/3f65b449-a945-4247-bcc2-e33d94a07cb6: ('Connection aborted.', error(113, 'EHOSTUNREACH'))\n"]
2015-10-23 18:20:32.368 1572 WARNING nova.scheduler.utils [req-20b92c63-df02-4c16-941e-5b7c0b68aa96 b476579221d74f1eb0474fb5d970dead eec1d66ee98a46458c98f2c84607c229 - - -] Failed to compute_task_build_instances: No valid host was found. There are not enough hosts available.
Traceback (most recent call last):

  File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 142, in inner
    return func(*args, **kwargs)

  File "/usr/lib/python2.7/site-packages/nova/scheduler/manager.py", line 86, in select_destinations
    filter_properties)

  File "/usr/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 80, in select_destinations
    raise exception.NoValidHost(reason=reason)

NoValidHost: No valid host was found. There are not enough hosts available.

Solution : Check firewall for Controller node