[neutron][ovn] ipv6 in virtual networks

Piotr Misiak piotrmisiak1984 at gmail.com
Wed Feb 10 18:11:21 UTC 2021

Hi all,

I have a test env with OpenStack Ussuri and OVN deployed by kolla-ansible.

I'm struggling with IPv6 VMs addressing. Has anyone deployed such
configuration successfully?

What is working:

 - SLAAC for VMs IPv6 addressing - VMs configure IPv6 addresses and can
ping each other via IPv6

 - VMs can ping virtual router's fe80:: address

 - OVN is sending ICMPv6 RA packets periodically on virtual private networks

What is not working:

 - VMs can't ping virtual router's private network IPv6 address
specified in virtual network configuration in Neutron (IPv6 GUA), I see
ICMPv6 echo request packets on tapXXXXX interfaces with a correct DEST
MAC, but there are no responses.

 - Routing is not working at all

Besides those, I can't imagine how upstream router will know how to
reach a particular private network with GUA IPv6 addresses (to which
virtual router send packets to reach a particular private network?). I
have a standard external network with IPv6 GUA /64 subnet and virtual
routers which connects private networks with IPv6 GUA /64 subnets with
external network. I thought that OVN virtual router will send ICMPv6 RA
packets on external network with reachable prefixes and upstream router
will learn routing info from those but I don't see any RA packets sent
by OVN on external network, I see only RA packets from an upstream
router. How this should work and be configured? How to configure GUA
IPv6 addresses on virtual private networks? Is it supported by Neutron/OVN?

Looking forward any responses regarding this area because documentation
does not exist technically.


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