[ISSUE] Failed to allocate the network(s), not rescheduling, Spawning new instances is fail OpenStack

Problem : 

When trying to Create new instances on OpenStack is fail.

Error Message:

Failed to allocate the network(s), not rescheduling.

Fixed and Solution: 

vi /etc/nova/nova.conf

#Fail instance boot if vif plugging fails
vif_plugging_is_fatal = False

#Number of seconds to wait for neutron vif
vif_plugging_timeout = 0

Referent URL:

https://ask.openstack.org/en/question/54531/failed-to-allocate-the-networks-not-rescheduling/
https://ask.openstack.org/en/question/26938/virtualinterfacecreateexception-virtual-interface-creation-failed/
https://ask.openstack.org/en/question/57342/spawning-new-instances-fails-to-allocate-the-network/