setup external VRFs

gistfile1.txt

#!/bin/bash

# Configuration Constants
LOCAL_IP="198.18.0.155"         # Host VTEP IP
ANYCAST_SVC_IP="172.27.187.82"  # The Shared Service IP
BGP_AS=64512                     # Your BGP AS

# 1. Global Kernel Tuning for VRF/Anycast
echo "Tuning kernel for Anycast VRF performance..."
sysctl -w net.ipv4.tcp_l3mdev_accept=1
sysctl -w net.ipv4.udp_l3mdev_accept=1
sysctl -w net.ipv4.ip_forward=1
sysctl -w net.ipv4.conf.all.forwarding=1
sysctl -w net.ipv4.conf.all.rp_filter=2

# 2. Base Bridge and VXLAN Setup
echo "Initializing Bridge (br0) and VXLAN (vxlan0)..."
ip link add br0 type bridge vlan_filtering 1 vlan_default_pvid 0
ip link set br0 addrgenmode none
ip link add vxlan0 type vxlan dstport 4789 local $LOCAL_IP nolearning external vnifilter
ip link set vxlan0 addrgenmode none master br0
bridge link set dev vxlan0 vlan_tunnel on neigh_suppress on learning off
ip link set br0 up
ip link set vxlan0 up

# Loop to create 72 VRFs with Anycast IPs
for i in $(seq 1 72); do
    VRF_NAME="vrf$i"
    VLAN_ID=$((1099 + i))   # 1100-1171
    VNI_ID=$((99 + i))      # 100-171
    TABLE_ID=$VLAN_ID

    echo "Configuring $VRF_NAME (VNI $VNI_ID) with Anycast IP..."

    # Create VRF
    ip link add $VRF_NAME type vrf table $TABLE_ID
    ip link set $VRF_NAME up

    # Bridge/VLAN Mapping
    bridge vlan add dev br0 vid $VLAN_ID self
    bridge vlan add dev vxlan0 vid $VLAN_ID
    bridge vni add dev vxlan0 vni $VNI_ID
    bridge vlan add dev vxlan0 vid $VLAN_ID tunnel_info id $VNI_ID

    # Create SVI and Assign Anycast IP
    SVI_NAME="${VRF_NAME}br"
    ip link add $SVI_NAME link br0 type vlan id $VLAN_ID
    ip link set $SVI_NAME master $VRF_NAME
    
    # Assign the IP - Linux allows the same IP on different VRF SVIs
    ip addr add ${ANYCAST_SVC_IP}/32 dev $SVI_NAME

    # ARP Suppression (Prevents IP conflicts on the bridge)
    sysctl -w net.ipv4.conf.${SVI_NAME}.arp_ignore=1
    sysctl -w net.ipv4.conf.${SVI_NAME}.arp_announce=2
    
    ip link set $SVI_NAME up

    # Build FRR Config string
    FRR_CMDS+="
configure terminal
vrf $VRF_NAME
 vni $VNI_ID
exit-vrf 
router bgp $BGP_AS vrf $VRF_NAME 
 address-family ipv4 unicast
  network $ANYCAST_SVC_IP/32
 exit-address-family
 address-family l2vpn evpn
  advertise ipv4 unicast
 exit-address-family
end"
done

# 3. Apply FRR Config
echo "Applying FRR/BGP configurations..."
podman exec frr vtysh -c "$FRR_CMDS"
podman exec frr vtysh -c "write memory"

# 4. Start Nginx on Host Network
echo "Starting Nginx in Host Network mode..."
podman stop shared-webserver 2>/dev/null || true
podman rm shared-webserver 2>/dev/null || true

podman run -d --name shared-webserver \
  --net=host \
  docker.io/library/nginx:latest

echo "Setup Complete. Service $ANYCAST_SVC_IP is now active in 72 VRFs."