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Neighbor Discovery Problems with Nova-Network and IPv6 (Havana)

asked 2014-07-24 10:02:10 -0500

hrzbrg gravatar image


I want to run Havana with Nova-Network and IPv6. The only valid resource I found for a multi-host setup is from Cybera. You can already see some comments below the post, but I want to reach out to more people.

My compute nodes have the flat_interface = eth2 and the flat_network_bridge = br100. The eth2 interface has no v4/v6 address and accept_ra = 0 and v6 forwarding = 0. The br100 (at the moment still a linux bridge) configures itself via SLAAC from a router that serves router advertisements to the network.

With nova-manage I created a network and pointed the gateway_v6 to my router. I worked around radvd with a simple "exit 0" executable file, just as mentioned in the above blog post.

Spawned instances get their v6 address and I can verify that they receive router advertisements and have a default route pointing to the link local address of the router. I created security groups with ::/0 to allow ICMP and SSH. On the compute node that hosts the instance I can access it over v6. But now the problems start and I tcpdumped a lot:

Ping from Router --> Instance: Neighbor Solicitation arrives on Instance. Instance sends Neighbor Advertisement back to Router [Flags: solicited, override], but the Router never gets it.

Ping from Instance --> Router: Neighbor Solicitation arrives on Router. Router sends NA back to Instance [Flags: router, solicited, override] but it does not arrive at the Instance. Destination unreachable: Address unreachable

Ping from Instance --> : On the Router I can see the requests going out and the replys coming in but the Instance is reporting a Destination unreachable.

Ping from v6 connected VM at Cybera --> Instance: On the Router I can see incoming traffic, but it is not reaching the Instance.

I googled a lot and stumbled over several suggestions including:

  • setting multicast_snooping=0 on br100
  • setting multicast_router=2 for the eth2 port in br100
  • setting proxy_ndp on/off on br100

None of it really solved it. At the moment I am stumbling in the dark because I don't know who is eating the Neighbor Advertisements.

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answered 2014-07-29 06:51:16 -0500

hrzbrg gravatar image

Since this was a testlab, the installation was in VirtualBox. After moving to vagrant-libvirt and starting the OpenStack boxes with kvm, the problem did not occur. So the problem seems to be in VirtualBox. It is not solved but circumvented for me.

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Asked: 2014-07-24 10:02:10 -0500

Seen: 658 times

Last updated: Jul 29 '14