OpenStack - OpenVSwitch Agent won't register

I hit the wall today when I tried to add an another compute node to my OpenStack. Everything seemed to install fine. However, the Openvswitch Agent did not register itself. Of course, I am using the Oracle Enterprise Linux which is not official supported yet by OpenStack and it made me uneasy. During the installation process, I hit a few problems of loading the wrong yum packages and I correct them manaully.

First I checked out neutron-openvswitch-agent.log on the compute node. There is no trace and error. I checked out the neutron-server.log, no trace and error neither.  I understand that the registration mechanism is by sending a report_status message from the agent to neutron controller.

I used rabbitmqctl to check for the existence of the queue and it did. It really buffled me. So I compared the message in the neutron-server.log.  With the surprise, the clock on the new compute node was not set correctly and the '_context_timestamp' is off in the debug messager.

2014-05-19 15:13:33.923 21639 DEBUG neutron.db.agents_db [req-915d3718-8489-4bd1-905f-3a02959b2746 None] Message with invalid timestamp received report_state /opt/stack/neutron/neutron/db/agents_db.py:214

So the time is the problem.  I adjusted the clock. Magically, the agent is registered. I hope there is much more clear message to idenify the problem.