Makes IP static for given virtual machine name in virt-manager

virt-static-ip.sh

#!/bin/bash

# Check if VM name is provided
VM_NAME=$1
if [ -z "$VM_NAME" ]; then
    echo "Makes IP static for given virtual machine name in virt-manager"
    echo "Usage: $0 <vm_name>"
    exit 1
fi

# 1. Get the MAC address and Network Name from the first interface
IFACE_INFO=$(virsh domiflist "$VM_NAME" | grep -E "network|bridge" | head -n 1)
MAC=$(echo "$IFACE_INFO" | awk '{print $5}')
NETWORK=$(echo "$IFACE_INFO" | awk '{print $3}')

if [ -z "$MAC" ] || [ -z "$NETWORK" ]; then
    echo "Error: Could not find network info for '$VM_NAME'. Is the VM using a 'Network' source?"
    exit 1
fi

# 2. Get the current IP address
# Try getting it from DHCP leases first, then fall back to the Guest Agent
IP=$(virsh domifaddr "$VM_NAME" --source lease | grep "$MAC" | awk '{print $4}' | cut -d'/' -f1)

if [ -z "$IP" ]; then
    IP=$(virsh domifaddr "$VM_NAME" --source agent | grep "ipv4" | head -n 1 | awk '{print $4}' | cut -d'/' -f1)
fi

if [ -z "$IP" ]; then
    echo "Error: Could not detect a running IP for '$VM_NAME'. Ensure the VM is running."
    exit 1
fi

echo "VM: $VM_NAME | MAC: $MAC | Current IP: $IP | Network: $NETWORK"

echo "Applying static reservation..."

# 3. Add the DHCP host entry to the libvirt network
# --live updates the running network; --config makes it survive reboots
virsh net-update "$NETWORK" add ip-dhcp-host \
    "<host mac='$MAC' name='$VM_NAME' ip='$IP' />" \
    --live --config

if [ $? -eq 0 ]; then
    echo "Success! $VM_NAME will now always receive $IP on the '$NETWORK' network."
else
    echo "Failed. (Note: If the entry already exists, this command will error.)"
fi