Add EVPN LAG Support

AI-assisted: Claude Code
Signed-off-by: Freerk-Ole Zakfeld <fzakfeld@scaleuptech.com>

Author: fzakfeld

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "git.ignoreLimitWarning": true
+}

osism/tasks/conductor/sonic/config_generator.py

@@ -274,7 +274,8 @@ def generate_sonic_config(device, hwsku, device_as_mapping=None, config_version=
         config["BREAKOUT_PORTS"].update(breakout_info["breakout_ports"])
 
     # Add port channel configuration
-    _add_portchannel_configuration(config, portchannel_info)
+    evpn_system_mac = device.config_context.get("_evpn_system_mac")
+    _add_portchannel_configuration(config, portchannel_info, evpn_system_mac)
 
     # Add VRF configuration
     _add_vrf_configuration(config, vrf_info, netbox_interfaces)
@@ -2067,17 +2068,20 @@ def _add_vrf_configuration(config, vrf_info, netbox_interfaces):
             )
 
 
-def _add_portchannel_configuration(config, portchannel_info):
+def _add_portchannel_configuration(config, portchannel_info, evpn_system_mac=None):
     """Add port channel configuration from NetBox."""
     if portchannel_info["portchannels"]:
         for pc_name, pc_data in portchannel_info["portchannels"].items():
             # Add PORTCHANNEL configuration
-            config["PORTCHANNEL"][pc_name] = {
+            pc_config = {
                 "admin_status": pc_data["admin_status"],
                 "fast_rate": pc_data["fast_rate"],
                 "min_links": pc_data["min_links"],
                 "mtu": pc_data["mtu"],
             }
+            if pc_data.get("evpn_lag") and evpn_system_mac:
+                pc_config["system_mac"] = evpn_system_mac
+            config["PORTCHANNEL"][pc_name] = pc_config
 
             # Add PORTCHANNEL_INTERFACE configuration to enable IPv6 link-local
             config["PORTCHANNEL_INTERFACE"][pc_name] = {

osism/tasks/conductor/sonic/constants.py

@@ -5,6 +5,9 @@
 # Tag to add AF L2VPN EVPN to BGP neighbor
 BGP_AF_L2VPN_EVPN_TAG = "bgp-af-l2vpn-evpn"
 
+# Tag to enable EVPN Multihoming (evpn-lag mode) on a port channel
+EVPN_LAG_TAG = "evpn-lag"
+
 # Default AS prefix for local ASN calculation
 DEFAULT_LOCAL_AS_PREFIX = 4200
 

osism/tasks/conductor/sonic/interface.py

@@ -7,7 +7,7 @@
 import re
 from loguru import logger
 
-from .constants import PORT_TYPE_TO_SPEED_MAP, HIGH_SPEED_PORTS, PORT_CONFIG_PATH
+from .constants import PORT_TYPE_TO_SPEED_MAP, HIGH_SPEED_PORTS, PORT_CONFIG_PATH, EVPN_LAG_TAG
 from .cache import get_cached_device_interfaces
 
 # Global cache for port configurations to avoid repeated file reads
@@ -1044,12 +1044,24 @@ def detect_port_channels(device):
 
                 # Initialize port channel if not exists
                 if portchannel_name not in portchannels:
+                    # Find the full LAG interface object to check tags
+                    lag_interface = next(
+                        (iface for iface in lag_interfaces if iface.id == lag_parent.id),
+                        None,
+                    )
+                    evpn_lag = False
+                    if lag_interface and hasattr(lag_interface, "tags") and lag_interface.tags:
+                        evpn_lag = any(
+                            tag.slug == EVPN_LAG_TAG for tag in lag_interface.tags
+                        )
+
                     portchannels[portchannel_name] = {
                         "members": [],
                         "admin_status": "up",
                         "fast_rate": "true",
                         "min_links": "1",
                         "mtu": "9100",
+                        "evpn_lag": evpn_lag,
                     }
 
                 # Add member to port channel