Comment 1 for bug 1185916

Édouard Thuleau (ethuleau) wrote :

When the load is too heavy (update dnsmasq host file and send lease update) on DHCP agent, the report state to Neutron server is delayed and the Neutron sever considers that agent is down and doesn't sent the port creation to the agent. So the dnsmasq host file isn't updated to serve that IP port's.

Do you have this log in agent log file :
2013-08-07 13:21:46 WARNING [quantum.openstack.common.loopingcall] task run outlasted interval by 2.375859 sec

You can increase the 'report_interval' flag on the agent and the 'agent_down_time' flag on the Neutron server side.
This problem should be corrected with this bp: https://blueprints.launchpad.net/neutron/+spec/remove-dhcp-lease.
Meanwhile, I think we should add log warning in the neutron server code to prevent that it cannot notify any DHCP agent for a port creation. And backport that on the Grizzly release.

What do you think ?