Le 20 nov. 2018 à 22:45, David Ahern <d...@cumulusnetworks.com> a écrit :
>
> On 11/20/18 7:23 AM, Alexis Bauvin wrote:
>> We are trying to isolate the VXLAN traffic from different VMs with VRF as
>> shown
>> in the schemas below:
>>
>> +-------------------------+ +----------------------------+
>> | +----------+ | | +------------+ |
>> | | | | | | | |
>> | | tap-red | | | | tap-blue | |
>> | | | | | | | |
>> | +----+-----+ | | +-----+------+ |
>> | | | | | |
>> | | | | | |
>> | +----+---+ | | +----+----+ |
>> | | | | | | | |
>> | | br-red | | | | br-blue | |
>> | | | | | | | |
>> | +----+---+ | | +----+----+ |
>> | | | | | |
>> | | | | | |
>> | | | | | |
>> | +----+--------+ | | +--------------+ |
>> | | | | | | | |
>> | | vxlan-red | | | | vxlan-blue | |
>> | | | | | | | |
>> | +------+------+ | | +-------+------+ |
>> | | | | | |
>> | | VRF | | | VRF |
>> | | red | | | blue |
>> +-------------------------+ +----------------------------+
>
> Roopa and I were discussing this setup and are puzzled by the VRF
> association here. Does br-red and br-blue have an address? The commands
> below do not show it and from our perspective seems odd for this
> scenario. If it does not have an address, then there is no reason for
> the VRF labeling.
Yes, br-red and br-blue have an address. Addresses (both MAC and IP)
are anycast addresses, to make an anycast gateway for the VMs behind
the taps. This serves for a classical evpn symmetric distributed
routing, both between vxlans and towards external networks. I am using
FRR as a control plane to exchange bgp-evpn information between
hypervisors.
The schematic could have been more complete, including more bridges
and more taps in the vrf, with an added bridge+vxlan for the l3vni.
I did not include them as I wanted to focus on the underlay itself
and not on what vxlan was used for.
Here is a more complete example:
+---------+
| |
| vrf1000 |
| |
+--+-+-+--+
| | |
+---------------------+ | +---------------+
| | |
+------+------+ +------+------+ +----+---+
| | | | | |
| br0 | | br1 | | br1000 |
| 10.0.0.1/24 | | 10.0.1.1/24 | | |
| | | | +----+---+
+----+-+-+----+ +-----+-+-----+ |
| | | | | |
+-------+ | +-------+ +--+ +---+ |
| | | | | |
+--+---+ +---+--+ +----+---+ +---+--+ +---+----+ +-----+-----+
| | | | | | | | | | | |
| tap0 | | tap1 | | vxlan0 | | tap2 | | vxlan1 | | vxlan1000 |
| | | | | | | | | | | |
+------+ +------+ +--------+ +------+ +--------+ +-----------+
. . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
. +---------+ +--------------+
. | | | |
. | vrf1001 | | vrf-underlay |
. | | | |
. +---+-+---+ +-------+------+
. | | |
. +---------+ +----------+ |
. | | |
. +------+------+ +----+---+ |
. | | | | |
. | br2 | | br1001 | |
. | 10.0.2.1/24 | | | |
. | | +----+---+ |
. +----+-+-+----+ | |
. | | | | |
. +-----+ | +-------+ | |
. | | | | +-------+-------+
. +---+--+ +--+---+ +---+----+ +-----+-----+ | |
. | | | | | | | | | eth0.2030 |
. | tap3 | | tap4 | | vxlan2 | | vxlan1001 | | 172.16.0.2/24 |
. | | | | | | | | | |
. +------+ +------+ +--------+ +-----------+ +---------------+
. . . ^ .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(vxlan lower device is eth0.2030) v
+----------------+
| |
| eth0 |
| 192.168.1.2/24 |
| |
+----------------+
In this example, the underlay is rather simple. A more complex case
could be with several uplinks in the underlay vrf, and a dummy/loopback
with a /32 ip, used as a vxlan lower device and to bind routing daemons
(e.g. bgpd).
+--------------+
| |
| vrf-underlay |
| |
+-----+-+-+----+
| | |
+---------------+ | +---------------+
| | |
+-------+-------+ +-------+-------+ +-------+--------+
| | | | | |
| eth1 | | eth2 | | dummy0 |
| 172.16.0.2/31 | | 172.16.0.4/31 | | 192.168.0.1/32 |
| | | | | |
+---------------+ +---------------+ +----------------+
.
. . . . . . . . . . . . . . . . . . . . . . .
(vxlan lower device is dummy0)
As for default vrf, it would contain for example management traffic. We
don’t want to mix the underlay routing tables to other traffics.
> Also, it would be good to have a unit test this case. Can you create a
> shell script that creates the setup and runs a few tests verifying
> connectivity? You can use network namespaces and veth pairs in place of
> the VM with a tap device. From there the functionality is the same.
> Tests can be initial VRF association for the vxlan lower device,
> changing the VRF to another device, and then changing again back to
> default VRF - checking proper connectivity for each.
Sure! I’ve just finished writing it, but I am not sure of the best way
so send it. I guess I will have to add it to a v4 of the patches, in
tools/testing/selftests/net?
> Thanks
