Public bug reported:
Hi,
We have observed instances failing to get a DHCP reply, either when booting for
the first time, or after a reboot.
By tcpdumping the traffic on the tap, then qvb and qvo interfaces, we can see
the DHCP request leaving, but it doesn't reach the neutron-gateway node where
the dhcp agent for the network runs.
If we remove and then re-add the network to the dhcp agent, it starts
working fine again.
I have dumped the output of `ovs-ofctl dump-flows br-tun` on the
neutron-gateway side, before and after doing the remove/add.
One difference I noted, was a rule appearing, with the mac of the VM which had
the issue:
cookie=0xb42e8d404b989e72, duration=13.344s, table=20, n_packets=0, n_bytes=0,
hard_timeout=300, idle_age=13,
priority=1,vlan_tci=0x0001/0x0fff,dl_dst=fa:16:3e:db:34:a3
actions=load:0->NXM_OF_VLAN_TCI[],load:0x20->NXM_NX_TUN_ID[],output:5201
However, this is a rule for packets from the dhcp agent to the VM, so
its absence doesn't explain why DHCP requests don't arrive to
destination.
The cloud is running neutron 8.4.0 (Mitaka), on ubuntu (16.04) machines.
Most of the time it works, but this problem comes back often enough that
it impacts users.
Thanks.
** Affects: neutron
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to neutron.
https://bugs.launchpad.net/bugs/1748894
Title:
intermittent dhcp failures
Status in neutron:
New
Bug description:
Hi,
We have observed instances failing to get a DHCP reply, either when booting
for the first time, or after a reboot.
By tcpdumping the traffic on the tap, then qvb and qvo interfaces, we can see
the DHCP request leaving, but it doesn't reach the neutron-gateway node where
the dhcp agent for the network runs.
If we remove and then re-add the network to the dhcp agent, it starts
working fine again.
I have dumped the output of `ovs-ofctl dump-flows br-tun` on the
neutron-gateway side, before and after doing the remove/add.
One difference I noted, was a rule appearing, with the mac of the VM which
had the issue:
cookie=0xb42e8d404b989e72, duration=13.344s, table=20, n_packets=0,
n_bytes=0, hard_timeout=300, idle_age=13,
priority=1,vlan_tci=0x0001/0x0fff,dl_dst=fa:16:3e:db:34:a3
actions=load:0->NXM_OF_VLAN_TCI[],load:0x20->NXM_NX_TUN_ID[],output:5201
However, this is a rule for packets from the dhcp agent to the VM, so
its absence doesn't explain why DHCP requests don't arrive to
destination.
The cloud is running neutron 8.4.0 (Mitaka), on ubuntu (16.04)
machines.
Most of the time it works, but this problem comes back often enough
that it impacts users.
Thanks.
To manage notifications about this bug go to:
https://bugs.launchpad.net/neutron/+bug/1748894/+subscriptions
--
Mailing list: https://launchpad.net/~yahoo-eng-team
Post to : [email protected]
Unsubscribe : https://launchpad.net/~yahoo-eng-team
More help : https://help.launchpad.net/ListHelp
