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Posted to users@cloudstack.apache.org by Júlíus Þór Bess <ju...@1984.is> on 2025/03/07 18:31:25 UTC

EVPN-VXLAN to the host type-2 MAC+IP routes

Hi guys,

I see that some of you are using or have been experimenting with 
EVPN-to-the-Host setup and I'd like to know how you are managing the 
neighbor table entries to produce the Type-2 MAC+IP advertisements. Are 
you using static entries added on VM startup (hook script, maybe?) or what?


Julius Thor

Re: EVPN-VXLAN to the host type-2 MAC+IP routes

Posted by Júlíus Þór Bess <ju...@1984.is>.
Hi Alex,

Thank you for the reply!

Advertise-svi-ip is for advertising the primary IP on the local 
gateway/SVI for a VNI or all VNI's, depending on where you put the knob 
in the config. That indeed does advertise a MAC+IP of the gateway and 
makes it reachable on the EVPN network. Usually that's not needed 
(because of the anycast-gw), unless you want to test reachability or use 
a VNI for a management network to reach the host.

But lets say that you start a VM and it talks to some host on the 
internet, in that case it needs to contact it's local anycast gateway 
and the local SVI learns it's IP and MAC and adds it to the neighbor 
table in kernel and FRR creates a type-2 MAC+IP route, all is good, it 
gets it data and goes silent. After a little while the neighbor entry, 
in kernel, times out (garbage collected) and gets thrown away, the 
Type-2 MAC+IP gets thrown away with it... Now, traffic entering the 
subnet towards the VM will most likely go through another hypervisor, 
thus taking a suboptimal path.

I hope I'm laying down the issue properly. So I'm wondering how this 
issue was solved in Cloudstack.

Best regards,
Julius Thor


On 7.3.2025 18:53, Alex Dietrich wrote:
> Hi Julius,
>
> When I deployed this, I did not have to do anything at the instance or VM startup to produce the MAC+IP routes. I may have had a line or two in the FRR configuration on the host to make sure it was advertising the Mac-IP automatically. It may have been ‘advertise-svi-ip’.
>
> The bigger challenge I had in integrating this with an existing EVPN VXLAN deployment was handling VNI mapping, which was not so fun 😊
>
> I did end up with a “successful” deployment, so let me know if I can be of further assistance.
>
> Thanks,
> Alex
>
>
> From: Júlíus Þór Bess <ju...@1984.is>
> Date: Friday, March 7, 2025 at 1:33 PM
> To: users@cloudstack.apache.org <us...@cloudstack.apache.org>
> Cc: wido@denhollander.io <wi...@denhollander.io>
> Subject: EVPN-VXLAN to the host type-2 MAC+IP routes
> EXTERNAL
>
> Hi guys,
>
> I see that some of you are using or have been experimenting with
> EVPN-to-the-Host setup and I'd like to know how you are managing the
> neighbor table entries to produce the Type-2 MAC+IP advertisements. Are
> you using static entries added on VM startup (hook script, maybe?) or what?
>
>
> Julius Thor

Re: EVPN-VXLAN to the host type-2 MAC+IP routes

Posted by Wido den Hollander <wi...@widodh.nl.INVALID>.

Op 10/03/2025 om 17:28 schreef Júlíus Þór Bess:
> 
> On 3/10/25 16:04, Wido den Hollander wrote:
>>
>>
>> Op 07/03/2025 om 19:53 schreef Alex Dietrich:
>>> Hi Julius,
>>>
>>> When I deployed this, I did not have to do anything at the instance 
>>> or VM startup to produce the MAC+IP routes. I may have had a line or 
>>> two in the FRR configuration on the host to make sure it was 
>>> advertising the Mac-IP automatically. It may have been ‘advertise- 
>>> svi-ip’.
>>>
>>
>>
>> Yes, that's it. No need to manually do anything.
>>
>> advertise-all-vni
>> advertise-svi-ip
>>
>> Also make sure you BGP neighbors are enabled under the EVPN family.
>>
> How is FRR informed of the IP's of the VMs? Does Cloudstack add static 
> neighbor entries?

The exact details I'd have to check, but Frr learns everything 
dynamically by looking at the local vxlan interface and the attached bridge.

MAC is learned from the bridge and those routes are being announced by Frr.

Wido

>>
>>> The bigger challenge I had in integrating this with an existing EVPN 
>>> VXLAN deployment was handling VNI mapping, which was not so fun 😊
>>>
>>> I did end up with a “successful” deployment, so let me know if I can 
>>> be of further assistance.
>>>
>>> Thanks,
>>>
>>> Alex
>>>
>>> *From: *Júlíus Þór Bess <ju...@1984.is>
>>> *Date: *Friday, March 7, 2025 at 1:33 PM
>>> *To: *users@cloudstack.apache.org <us...@cloudstack.apache.org>
>>> *Cc: *wido@denhollander.io <wi...@denhollander.io>
>>> *Subject: *EVPN-VXLAN to the host type-2 MAC+IP routes
>>>
>>> EXTERNAL
>>>
>>> Hi guys,
>>>
>>> I see that some of you are using or have been experimenting with
>>> EVPN-to-the-Host setup and I'd like to know how you are managing the
>>> neighbor table entries to produce the Type-2 MAC+IP advertisements. Are
>>> you using static entries added on VM startup (hook script, maybe?) or 
>>> what?
>>>
>>>
>>> Julius Thor
>>>
>>

Re: EVPN-VXLAN to the host type-2 MAC+IP routes

Posted by Júlíus Þór Bess <ju...@1984.is>.
On 3/10/25 16:04, Wido den Hollander wrote:
>
>
> Op 07/03/2025 om 19:53 schreef Alex Dietrich:
>> Hi Julius,
>>
>> When I deployed this, I did not have to do anything at the instance 
>> or VM startup to produce the MAC+IP routes. I may have had a line or 
>> two in the FRR configuration on the host to make sure it was 
>> advertising the Mac-IP automatically. It may have been 
>> ‘advertise-svi-ip’.
>>
>
>
> Yes, that's it. No need to manually do anything.
>
> advertise-all-vni
> advertise-svi-ip
>
> Also make sure you BGP neighbors are enabled under the EVPN family.
>
How is FRR informed of the IP's of the VMs? Does Cloudstack add static 
neighbor entries?
>
>> The bigger challenge I had in integrating this with an existing EVPN 
>> VXLAN deployment was handling VNI mapping, which was not so fun 😊
>>
>> I did end up with a “successful” deployment, so let me know if I can 
>> be of further assistance.
>>
>> Thanks,
>>
>> Alex
>>
>> *From: *Júlíus Þór Bess <ju...@1984.is>
>> *Date: *Friday, March 7, 2025 at 1:33 PM
>> *To: *users@cloudstack.apache.org <us...@cloudstack.apache.org>
>> *Cc: *wido@denhollander.io <wi...@denhollander.io>
>> *Subject: *EVPN-VXLAN to the host type-2 MAC+IP routes
>>
>> EXTERNAL
>>
>> Hi guys,
>>
>> I see that some of you are using or have been experimenting with
>> EVPN-to-the-Host setup and I'd like to know how you are managing the
>> neighbor table entries to produce the Type-2 MAC+IP advertisements. Are
>> you using static entries added on VM startup (hook script, maybe?) or 
>> what?
>>
>>
>> Julius Thor
>>
>

Re: EVPN-VXLAN to the host type-2 MAC+IP routes

Posted by Wido den Hollander <wi...@widodh.nl.INVALID>.

Op 07/03/2025 om 19:53 schreef Alex Dietrich:
> Hi Julius,
> 
> When I deployed this, I did not have to do anything at the instance or 
> VM startup to produce the MAC+IP routes. I may have had a line or two in 
> the FRR configuration on the host to make sure it was advertising the 
> Mac-IP automatically. It may have been ‘advertise-svi-ip’.
> 


Yes, that's it. No need to manually do anything.

advertise-all-vni
advertise-svi-ip

Also make sure you BGP neighbors are enabled under the EVPN family.

Wido

> The bigger challenge I had in integrating this with an existing EVPN 
> VXLAN deployment was handling VNI mapping, which was not so fun 😊
> 
> I did end up with a “successful” deployment, so let me know if I can be 
> of further assistance.
> 
> Thanks,
> 
> Alex
> 
> *From: *Júlíus Þór Bess <ju...@1984.is>
> *Date: *Friday, March 7, 2025 at 1:33 PM
> *To: *users@cloudstack.apache.org <us...@cloudstack.apache.org>
> *Cc: *wido@denhollander.io <wi...@denhollander.io>
> *Subject: *EVPN-VXLAN to the host type-2 MAC+IP routes
> 
> EXTERNAL
> 
> Hi guys,
> 
> I see that some of you are using or have been experimenting with
> EVPN-to-the-Host setup and I'd like to know how you are managing the
> neighbor table entries to produce the Type-2 MAC+IP advertisements. Are
> you using static entries added on VM startup (hook script, maybe?) or what?
> 
> 
> Julius Thor
>

Re: EVPN-VXLAN to the host type-2 MAC+IP routes

Posted by Alex Dietrich <ad...@ussignal.com.INVALID>.
Hi Julius,

When I deployed this, I did not have to do anything at the instance or VM startup to produce the MAC+IP routes. I may have had a line or two in the FRR configuration on the host to make sure it was advertising the Mac-IP automatically. It may have been ‘advertise-svi-ip’.

The bigger challenge I had in integrating this with an existing EVPN VXLAN deployment was handling VNI mapping, which was not so fun 😊

I did end up with a “successful” deployment, so let me know if I can be of further assistance.

Thanks,
Alex


From: Júlíus Þór Bess <ju...@1984.is>
Date: Friday, March 7, 2025 at 1:33 PM
To: users@cloudstack.apache.org <us...@cloudstack.apache.org>
Cc: wido@denhollander.io <wi...@denhollander.io>
Subject: EVPN-VXLAN to the host type-2 MAC+IP routes
EXTERNAL

Hi guys,

I see that some of you are using or have been experimenting with
EVPN-to-the-Host setup and I'd like to know how you are managing the
neighbor table entries to produce the Type-2 MAC+IP advertisements. Are
you using static entries added on VM startup (hook script, maybe?) or what?


Julius Thor