Feat(eos_designs): Add RD and RT override for VRFs

[bjmeuer]

Change Summary

Added the possibility to override the RD and RT values for VRFs.

Related Issue(s)

Fixes #3296

Component(s) name

arista.avd.eos_designs

Proposed changes

Added RD and RT override for VRFs in similar way it was already available for l2vlans

tenants:
  - name: TENANT1
    mac_vrf_vni_base: 10000
    vrfs:
      - name: VRF1
        vrf_id: 1
        rd_override: 111:222
        rt_override: 333:444
        ...
      - name: VRF2
        vrf_id: 2
        rd_override: 999
        rt_override: 999
        ...

How to test

tenants:
  - name: TENANT1
    mac_vrf_vni_base: 10000
    vrfs:
      - name: VRF1
        vrf_id: 1
        rd_override: 111:222
        rt_override: 333:444
        ...
      - name: VRF2
        vrf_id: 2
        rd_override: 999
        rt_override: 999
        ...

Checklist

User Checklist

• N/A

Repository Checklist

• My code has been rebased from devel before I start
• I have read the CONTRIBUTING document.
• My change requires a change to the documentation and documentation have been updated accordingly.
• I have updated molecule CI testing accordingly. (check the box if not applicable)

[philippebureau]

Tested, LGTM
I would commit Carl`s suggestions on the documentation

[carlbuchmann]

LGTM, small suggestion on the documentation

[bjmeuer]

LGTM, small suggestion on the documentation

Thanks for the review, I commited your suggestions

[carlbuchmann]

LGTM

[forcecity]

I have 2 points to double check with you:

1. You have added rt_override, but for the logic of it, I’m just a little bit confused from your source code (router_bgp.py):
   `def get_vrf_rt(self, vrf: dict) -> str:
   """
   Return a string with the route-target for one VRF
   """
   rt_override = default(vrf.get("rt_override"))

    if ":" in str(rt_override):
        return rt_override
   
    if rt_override is not None:
        return f"{rt_override}:{rt_override}"
    elif self._vrf_rt_admin_subfield is not None:
        admin_subfield = self._vrf_rt_admin_subfield
    elif self.shared_utils.overlay_rt_type["vrf_admin_subfield"] == "vrf_vni":
        admin_subfield = self.get_vrf_vni(vrf)
    else:
        # Both for 'id' and 'vrf_id' options.
        admin_subfield = self.get_vrf_id(vrf)
    return f"{admin_subfield}:{self.get_vrf_id(vrf)}"
   

`
On this line: return f"{rt_override}:{rt_override}", would it be return f”{ admin_subfield }:{ rt_override }”? Or you could define a new var like “assigned_number_subfield” and assign the rt_override value to it.

If I understand correctly from the eos_designs.schema, A single number will be used in the RT assigned number subfield (second part of the RT). But if you specify like the yellow line, the result will be different. By default, the “admin_subfield” will be vrf_id, and if I set different vrf_id and rt_override. In our deployment, it should be OK, but other customers may confuse about this behavior. What do you think?
2. I think there is a typo in schema (arista/avd/roles/eos_designs/schemas/schema_fragments/defs_network_services.schema.yml), line 308, it should be "the VRF RT will be derived"

[ClausHolbechArista]

@forcecity very good catch! We should also be respecting the admin_subfield setting if you give rt_override (without colon). I will fix this in a new PR.