[neutron] DevStack with IPv6

Lucio Seki lucioseki at gmail.com
Thu Sep 12 21:49:26 UTC 2019


Hi folks, I'm having troubles to ping6 a VM running over DevStack from its
hypervisor.
Could you please help me troubleshooting it?

I deployed DevStack with NEUTRON_CREATE_INITIAL_NETWORKS=False,
and manually created the networks, subnets and router. Following is my
router:

$ openstack router show router1 -c external_gateway_info -c interfaces_info
+-----------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field                 | Value


                                                                   |
+-----------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| external_gateway_info | {"network_id":
"b87048ed-1be9-4f31-8d7e-fe74921aeec4", "enable_snat": true,
"external_fixed_ips": [{"subnet_id":
"28a00bc3-b30b-456f-b26a-44b50d37183f", "ip_address": "10.2.0.199"},
{"subnet_id": "a9729beb-b297-4fec-8ec3-7703f7f6f4bc", "ip_address":
"fd12:67:1::3c"}]} |
| interfaces_info       | [{"subnet_id":
"081e8508-4ceb-4aaf-bf91-36a1e22a768c", "ip_address": "fd12:67:1:1::1",
"port_id": "75391abd-8ac8-41f8-acf8-3dfaf2a6b08f"}]

                              |
+-----------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

I'm trying to ping6 the following VM:

$ openstack server list
+--------------------------------------+---------+--------+------------------------------------------+--------+--------+
| ID                                   | Name    | Status | Networks
                          | Image  | Flavor |
+--------------------------------------+---------+--------+------------------------------------------+--------+--------+
| 938854d0-80e9-45b2-bc29-8fe7651ffa93 | manila1 | ACTIVE |
private1=fd12:67:1:1:f816:3eff:fe0e:17c3 | manila | manila |
+--------------------------------------+---------+--------+------------------------------------------+--------+--------+

I intend to reach it via br-ex interface of the hypervisor:

$ ip a show dev br-ex
9: br-ex: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state
UNKNOWN group default qlen 1000
    link/ether 0e:82:a1:ba:77:4c brd ff:ff:ff:ff:ff:ff
    inet6 fd12:67:1::1/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::c82:a1ff:feba:774c/64 scope link
       valid_lft forever preferred_lft forever

The hypervisor has the following routes:

$ ip -6 route
fd12:67:1:1::/64 via fd12:67:1::3c dev br-ex metric 1024 pref medium
fe80::/64 dev ens3 proto kernel metric 256 pref medium
fe80::/64 dev br-ex proto kernel metric 256 pref medium
fe80::/64 dev br-int proto kernel metric 256 pref medium
fe80::/64 dev tapa5cf4799-9f proto kernel metric 256 pref medium

And within the VM has the following routes:

root at ubuntu:~# ip -6 route
root at ubuntu:~# ip -6 route
fd12:67:1::/64 via fd12:67:1:1::1 dev ens3 metric 1024 pref medium
fd12:67:1:1::/64 dev ens3 proto kernel metric 256 expires 86360sec pref
medium
fe80::/64 dev ens3 proto kernel metric 256 pref medium
default via fe80::f816:3eff:feb3:bd56 dev ens3 proto ra metric 1024 expires
260sec hoplimit 64 pref medium

Though the ping6 from VM to hypervisor doesn't work:
root at ubuntu:~# ping6 fd12:67:1::1 -c4
PING fd12:67:1::1 (fd12:67:1::1): 56 data bytes
--- fd12:67:1::1 ping statistics ---
4 packets transmitted, 0 packets received, 100% packet loss

I'm able to tcpdump inside the router1 netns and see that request packet is
passing there, but can't see any reply packets:

$ sudo ip netns exec qrouter-5172472c-bbe7-4907-832a-e2239c8badb4 tcpdump
-l -i any icmp6
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144
bytes
21:29:29.351358 IP6 fd12:67:1:1:f816:3eff:fe0e:17c3 > fd12:67:1::1: ICMP6,
echo request, seq 0, length 64
21:29:30.033316 IP6 fe80::f816:3eff:feb3:bd56 > fe80::f816:3eff:fe0e:17c3:
ICMP6, neighbor solicitation, who has fe80::f816:3eff:fe0e:17c3, length 32
21:29:30.035807 IP6 fe80::f816:3eff:fe0e:17c3 > fe80::f816:3eff:feb3:bd56:
ICMP6, neighbor advertisement, tgt is fe80::f816:3eff:fe0e:17c3, length 24
21:29:30.353646 IP6 fd12:67:1:1:f816:3eff:fe0e:17c3 > fd12:67:1::1: ICMP6,
echo request, seq 1, length 64
21:29:31.355410 IP6 fd12:67:1:1:f816:3eff:fe0e:17c3 > fd12:67:1::1: ICMP6,
echo request, seq 2, length 64
21:29:32.357239 IP6 fd12:67:1:1:f816:3eff:fe0e:17c3 > fd12:67:1::1: ICMP6,
echo request, seq 3, length 64

The same happens from hypervisor to VM. I only acan see the request
packets, but no reply packets.

Thanks in advance,
Lucio Seki
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