Mailing List Archive

[neutron]Why there is an extra router interface in the qrouter namespace in DVR mode?
Hi folks,

I have a DVR-enabled cluster made of a controller, network, and compute
node. The *agent_mode* is set as *dvr_snat* on the network node, and *dvr*
on the compute node. The north-south traffic works in both SNAT and the
floating IP scenarios, but I cannot explain the extra interface shown up in
the Horizon dashboard for every tenant router. More details as below:

*ip netns* output on the compute node:

[image: image.png]

*ip addr show* from within the router namespace on the compute node:

[image: image.png]

*Notice there is only *one* *qr* interface, the gateway, for the tenant
subnet.

Here is the display from the Horizon dashboard router interface page:
[image: image.png]

Do you see the extra interface (*da7884d9-2ff1*)? The only place I can find
it is from inside the additional routing table in the router namespace:

[image: image.png]

[image: image.png]

What does that extra interface come from and what is it for? Why does it
show up in the dashboard, but not in the command line output?

Thank you all in advance.

Cody
Re: [neutron]Why there is an extra router interface in the qrouter namespace in DVR mode? [ In reply to ]
I didn't realize that inline screenshots would be scrubbed. Below is a
re-edited version of my original post.

Cody

---
Hi folks,

I have a DVR-enabled cluster made of a controller, network, and
compute node. The agent_mode is set to dvr_snat on the network node
and dvr on the compute node. North-south traffic works fine in both
SNAT and the floating IP scenarios. The only thing I cannot explain is
the extra interface shown in the Horizon dashboard for tenant routers.
Here are details:

'ip netns' output on the compute node:

[root@compute ~]# ip netns
fip-eadd51b1-1b0a-4504-b694-4f54b7b60d3d (id: 1)
qrouter-b7570af0-42f6-499d-bbf0-2139a98bc0a3 (id: 0)

'ip addr show' from within the router namespace on the compute node:

[root@compute ~]# ip netns exec
qrouter-b7570af0-42f6-499d-bbf0-2139a98bc0a3 ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: rfp-b7570af0-4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UP group default qlen 1000
link/ether ca:08:94:69:b9:6c brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet 169.254.106.114/31 scope global rfp-b7570af0-4
valid_lft forever preferred_lft forever
inet6 fe80::c808:94ff:fe69:b96c/64 scope link
valid_lft forever preferred_lft forever
13: qr-bd3e180e-2d: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc
noqueue state UNKNOWN group default qlen 1000
link/ether fa:16:3e:c4:a8:3c brd ff:ff:ff:ff:ff:ff
inet 192.168.0.1/24 brd 192.168.0.255 scope global qr-bd3e180e-2d
valid_lft forever preferred_lft forever
inet6 fe80::f816:3eff:fec4:a83c/64 scope link
valid_lft forever preferred_lft forever

Notice there is only one qr interface in the preceding output, but the
Horizon dashboard shows an extra interface for the same router:

Name Fixed IPs
(bd3e180e-2dd6) 192.168.0.1
(da7884d9-2ff1) 192.168.0.5

My questions are where the interface (da7884d9-2ff1) comes from and
what it does. Thank you!

Cody





On Sun, Aug 5, 2018 at 7:55 PM Cody <codeology.lab@gmail.com> wrote:
>
> Hi folks,
>
> I have a DVR-enabled cluster made of a controller, network, and compute node. The agent_mode is set as dvr_snat on the network node, and dvr on the compute node. The north-south traffic works in both SNAT and the floating IP scenarios, but I cannot explain the extra interface shown up in the Horizon dashboard for every tenant router. More details as below:
>
> ip netns output on the compute node:
>
>
>
> ip addr show from within the router namespace on the compute node:
>
>
>
> *Notice there is only one qr interface, the gateway, for the tenant subnet.
>
> Here is the display from the Horizon dashboard router interface page:
>
>
> Do you see the extra interface (da7884d9-2ff1)? The only place I can find it is from inside the additional routing table in the router namespace:
>
>
>
>
> What does that extra interface come from and what is it for? Why does it show up in the dashboard, but not in the command line output?
>
> Thank you all in advance.
>
> Cody
>

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