[Rdo-list] intermittent dhcp problem

[Zhao, Xin]

Hello,

I have a multi-node icehouse deployment (one controller, one network and 
one compute node), using neutron ML2 and openvswitch/VLAN networking, 
based on RDO on RHEL6.  Everything seems to work fine.

But once in a while, new instances can't get IP anymore, the syslog 
shows errors like "DHCPDISCOVER .... no address available", neutron DB 
shows the IP is allocated, but the DHCP conf file (eg. 
/var/lib/neutron/dhcp/XXXXXX/host) doesn't have it. No particular error 
messages from the dhcp agent log file. Restarting dhcp agent doesn't fix 
it. I have to restart all neutron services, including openvswitch 
daemon, to get the system back.

Another issue I notice is, on the network node, dmesg shows the 
following errors repeatedly, even when the networking services appear to 
be working fine :
"......
tap84e6f9d1-c2: hw csum failure.
Pid: 0, comm: swapper Not tainted 2.6.32-431.5.1.el6.x86_64 #1
Call Trace:
  <IRQ>  [<ffffffff8145bbf2>] ? netdev_rx_csum_fault+0x42/0x50
  [<ffffffff81454200>] ? __skb_checksum_complete_head+0x60/0x70
......
"

Below after my signature are some system information of the network node.

Any ideas on what's going on and how to debug it?

Thanks a lot,
Xin

# uname -a
Linux cldnet02.cloud.local 2.6.32-431.5.1.el6.x86_64 #1 SMP Tue Feb 11 
13:30:01 CST 2014 x86_64 x86_64 x86_64 GNU/Linux

# rpm -qa | grep neutron
python-neutronclient-2.3.4-4.el6.noarch
openstack-neutron-2014.1.2-1.el6.noarch
openstack-neutron-ml2-2014.1.2-1.el6.noarch
python-neutron-2014.1.2-1.el6.noarch
openstack-neutron-openvswitch-2014.1.2-1.el6.noarch

# rpm -qa | grep openvswitch
openvswitch-1.11.0_8ce28d-1.el6ost.x86_64
openstack-neutron-openvswitch-2014.1.2-1.el6.noarch

the NIC for the VM network:
# ethtool -i p1p2
driver: myri10ge
version: 1.5.1-1.451
firmware-version: 1.4.52 -- 2010/10/28 21:27:06 m
bus-info: 0000:06:00.0
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: no

the NIC for the management network:
# ethtool -i em1
driver: bnx2
version: 2.2.3
firmware-version: 4.6.8 bc 4.6.4 NCSI 1.0.6
bus-info: 0000:01:00.0
supports-statistics: yes
supports-test: yes
supports-eeprom-access: yes
supports-register-dump: yes
supports-priv-flags: no

the NIC for the external network:
# ethtool -i p1p1
driver: myri10ge
version: 1.5.1-1.451
firmware-version: 1.4.52 -- 2010/10/28 21:27:06 m
bus-info: 0000:05:00.0
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: no