MLAG anycast VTEP support

[jbemmel]

I would like to add support for https://docs.nvidia.com/networking-ethernet-software/cumulus-linux-59/Network-Virtualization/VXLAN-Active-Active-Mode/

i.e. in the vxlan module add a 'use_mlag_vtep' flag and select an anycast IP for node.vxlan.mlag_vtep (e.g. from the loopback pool)

[ssasso]

I created this plugin in the past for my own use case, maybe the code can help:

https://github.com/ssasso/netsim-topologies/blob/main/multivendor-evpn/_plugins/vxlan_anycast_plugin.py

[ipspace]

All the functionality is there:

• Add an extra loopback link for every node
• Set a static IP on that link
• Use vxlan.vtep attribute https://netlab.tools/module/vxlan/#changing-the-vxlan-vtep-source-interface-address on the link

I agree it's not exactly elegant, and might be a bit of a chore to get working on devices that believe in a single loopback interface. If you feel you need something better, plugin is the way to go.

[jbemmel]

@ssasso Thanks, very similar except the groups would be mlag pairs. Mind if I borrow that code?

[jbemmel]

@ipspace thanks, I’d need a plugin to generate the correct NVUE stanza to provision the anycast vtep ip on both mlag peers

[jbemmel]

Implemented in #1917