Role mapping

Developer Guide

Role names are PyAVD-version-sensitive — see the overview for the pinned version.

Infrahub's DcimDevice.role.value is a string enum that the hostvars generator maps to a PyAVD type. The mapping lives in src/solution_arista_avd/avd.py:

Table

Infrahub role	PyAVD type	Primary scenario
super_spine	super-spine	L3LS, 5-stage Clos
spine	spine	L3LS
leaf	l3leaf	L3LS
border_leaf	l3leaf	Dual-DC (DCI)
l2leaf	l2leaf	L3LS access, L2LS access, campus access
l2spine	l2spine	Standalone L2LS fabric
l3spine	l3spine	L2LS (L3 variant), campus core
p	p	ISIS-LDP IPVPN (provider core)
pe	pe	ISIS-LDP IPVPN (provider edge)
rr	rr	ISIS-LDP IPVPN route reflector

All PyAVD type values above are valid entries in the pinned PyAVD default node_type_keys. Roles beyond l3leaf/l2leaf are the schema anchors for the AVD example scenarios; the scenario-specific rendering behaviour is delivered either natively or through the avd_custom_hostvars escape hatch — see Extending the Pipeline.

The mapping in code

# src/solution_arista_avd/avd.py
ROLE_TO_AVD_TYPE: dict[str, str] = {
    "super_spine": "super-spine",
    "spine": "spine",
    "leaf": "l3leaf",
    "border_leaf": "l3leaf",
    "l2leaf": "l2leaf",
    "l2spine": "l2spine",
    "l3spine": "l3spine",
    "p": "p",
    "pe": "pe",
    "rr": "rr",
}


def get_avd_type(role: str) -> str:
    if role not in ROLE_TO_AVD_TYPE:
        msg = f"Unknown device role: {role}"
        raise ValueError(msg)
    return ROLE_TO_AVD_TYPE[role]

An unrecognized role raises ValueError at generation time — Phase 1 fails for that device.

Underlay-driven role selection

The four non-L3LS example designs do not set spine/leaf roles manually. Instead the upstream generator derives them from the fabric underlay, so the same spine/leaf topology renders different device types per design:

Fabric underlay	Spine-tier role	Leaf-tier role	Example design
none	l2spine	l2leaf	Standalone L2LS
ospf	l3spine	l2leaf	Campus
isis-ldp	p	pe	MPLS ISIS-LDP IPVPN

These come from SPINE_ROLE_BY_UNDERLAY and LEAF_ROLE_BY_UNDERLAY in avd.py. The selection is gated to non-L3LS underlays only: a routed L3LS fabric (underlay ebgp) is not in either map, so it falls back to the default spine / leaf roles.

MLAG in non-L3LS designs

MLAG_MAIN_TIER_ROLES (l2leaf, l2spine, l3spine) is the main tier of the non-L3LS designs that forms MLAG pairs. When the fabric underlay is one of SPINE_UPLINK_UNDERLAYS (none, ospf, isis-ldp), devices in these roles render node-group / peer-link / MLAG-domain configuration — the same as the L3LS leaf family. The gate leaves the L3LS access-tier l2leaf (pure access under EVPN) unaffected.

Which generator forms the pair depends on the tier:

Tier	Generator	Peer-link source
l2leaf (rack tier)	generate-rack	Highest-numbered free access ports — the arista-7050sx3-48yc8c l2leaf model ships no dedicated mlag_peer interfaces
l2spine (pod tier, underlay none)	generate-pod	Highest-numbered free super-spine-facing ports, unused in a standalone L2LS fabric (it has no super-spines)

Both go through the shared assign_mlag_peer_interfaces helper on the generator mixin, so the choice is deterministic (ordered by the interface's computed index) and idempotent — a re-run converts nothing further. The l2spine pair has no BGP ASN: a pure Layer-2 tier runs no BGP.

Per-tier spanning-tree priorities

Network.SpanningTreePriority links a fabric to a per-role MSTP priority. Its role dropdown covers super_spine, spine, leaf, l2leaf and — for the non-L3LS designs — l2spine and l3spine. The L2LS example sets l2spine: 4096 / l2leaf: 16384, which the hostvars generator emits as each tier's spanning_tree_priority.

Role implications

The role governs these downstream behaviors in the hostvars generator and in PyAVD itself:

Role	Uplink source	Gets EVPN data?	MLAG?
super_spine	— (top of fabric)	No	No
spine	super_spine	No	No
leaf	spine	Yes	Yes (if peer set)
border_leaf	spine	Yes, including DCI links and EVPN Gateway when the device is a member of an EvpnGatewayGroup	Yes (if peer set)
l2leaf	leaf	No (skipped)	Yes (if peer set)

See Hostvars Reference for exactly which fields each role emits.

Tests

The role mapping is exercised by:

• tests/unit/test_avd.py — covers get_avd_type() for each role and the ValueError on unknown roles.

Adding a new role

See Extending the Pipeline → Add a new device role.