EVPN A/A How to use unique VTEP IP and not anycast one

[onurgashi]

Summary

In cases where A/A is implemented, we most likely will run unique ASN per leaf, and no peer-link between.
This pushes the config to:

• Use unique ASN per leaf
• Use unique IP for loopback as source for VXLAN

In such cases we should not define loopback1 as there is no common loopback needed, and live with loopback0 that can be used as source.

We should define a knob that by default is true, but can be false so it won't create loopback1 and will change vxlan source interface in case of A/A.

vxlan_source_interface_lo1: false

Component Name

eos_designs.eos_l3ls_evpn

Expected results

Vxlan1 to use Lo0 as source.

[lermilov]

Possible fix:

1. Within /base/fabric/interfaces/leaf-vtep-vxlan-tunnel-loopback.j2:

{# Leaf VTEP vxlan tunnel loopback source interface #}
{% if vxlan_source_interface_lo1 is defined and vxlan_source_interface_lo1 == true %}}
  Loopback1:
    description: VTEP_VXLAN_Tunnel_Source
    shutdown: false
...
{% endif %}

2. Within base/tenant_evpn_vxlan/leaf_vxlan_vtep_interface:

{# vxlan-vtep interface #}
  Vxlan1:
    description: {{ inventory_hostname }}_VTEP
{% if vxlan_source_interface_lo1 is defined and vxlan_source_interface_lo1 == false %}
    source_interface: Loopback0
{% else %}
    source_interface: Loopback1
{% endif %}
...

3. Add vxlan_source_interface_lo1: true to eos_l3ls_evpn defaults variables

[onurgashi]

Solution @titom73 is really good actually, just doing mlag: false, we create unique IP per Leaf for Vxlan1.
I guess only drawback is the additional interface / IP block.

[titom73]

In case you don't want MLAG configured in a node group, you can configure mlag: false and then it will generate a Loopback1 IP per device and not shared across devices.

Inventory configuration:

l3leaf:
    EAPI_LEAF3:
      bgp_as: 65103
      mlag: false
      filter:
        tenants: [ 'Tenant_A', 'Tenant_B' ]
        tags: [ 'POD03', 'DC1' ]
      nodes:
        EAPI-LEAF3A:
          id: 5
          mgmt_ip: 10.73.254.17/24
          mac_address: '0c:1d:c0:1d:62:01'
          spine_interfaces: [Ethernet7, Ethernet7]
        EAPI-LEAF4A:
          id: 6
          mgmt_ip: 10.73.254.18/24
          mac_address: '0c:1d:c0:1d:62:01'
          spine_interfaces: [Ethernet8, Ethernet8]

And then structured configuration reports 2 different Loopback1

EAPI-LEAF3A

loopback_interfaces:
  Loopback1:
    description: VTEP_VXLAN_Tunnel_Source
    shutdown: false
    ip_address: 192.168.254.7/32
    isis_enable: EVPN_UNDERLAY
    isis_passive: true

EAPI-LEAF4A

loopback_interfaces:
  Loopback1:
    description: VTEP_VXLAN_Tunnel_Source
    shutdown: false
    ip_address: 192.168.254.8/32
    isis_enable: EVPN_UNDERLAY
    isis_passive: true

[onurgashi]

This, I guess from the feedback solves it partially. We would still need to define per node bgp_as: as that's typical in such designs with A/A.