rhel-osp-director: 8.0 bulk introspecting 8 nodes with default range (192.0.2.100,192.0.2.120), the last node doesn't get an IP and causes the introspection to stuck.


Environment:
openstack-ironic-conductor-4.2.2-3.el7ost.noarch
python-ironic-inspector-client-1.2.0-5.el7ost.noarch
dnsmasq-2.66-14.el7_1.x86_64
openstack-ironic-inspector-2.2.2-1.el7ost.noarch
openstack-ironic-api-4.2.2-3.el7ost.noarch
python-ironicclient-0.8.1-1.el7ost.noarch
openstack-ironic-common-4.2.2-3.el7ost.noarch
dnsmasq-utils-2.66-14.el7_1.x86_64


Steps to reproduce:
Attempt to bulk introspect 8 nodes or more with the default introspection range.

Result:
The introspection doesn't finish.
Checking the console of the node - it doesn't get an IP.
Looking at the logs:
Jan 07 20:31:56 instack.localdomain dnsmasq-dhcp[30022]: DHCPNAK(br-ctlplane) 192.0.2.105 00:ed:dc:54:1d:42 address in use
Jan 07 20:31:57 instack.localdomain dnsmasq-dhcp[30022]: DHCPNAK(br-ctlplane) 192.0.2.105 00:ed:dc:54:1d:42 address in use
Jan 07 20:31:57 instack.localdomain dnsmasq-dhcp[30022]: DHCPNAK(br-ctlplane) 192.0.2.105 00:ed:dc:54:1d:42 address in use


Note: Enlarged the range and restarted the openstack-ironic-inspector.service and openstack-ironic-inspector.service services. Restarted the introspection - completed successfully. Reduced the range to default and restarted the same services - the introspection got stuck again with the same issue.


Expected result:
Bulk introspection completed successfully for all nodes as long as their count doesn't go above the range.