Persist DHCP provisioned IP config (Debian, Ubuntu, netplan)

setup_net.sh

#!/bin/bash

# Interface name
IFACE="enp1s0"

# Get current IP, netmask, and gateway
IP=$(ip addr show $IFACE | grep 'inet ' | awk '{print $2}')
GATEWAY=$(ip route | grep default | awk '{print $3}')
DNS=$(awk '/^nameserver/ {print $2}' /run/systemd/resolve/resolv.conf | tr '\n' ' ')

# Backup current Netplan configuration
cp /etc/netplan/01-netcfg.yaml /etc/netplan/01-netcfg.yaml.backup

# Write new config to the Netplan configuration file
cat <<EOT > /etc/netplan/01-netcfg.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    $IFACE:
      dhcp4: no
      addresses: [$IP]
      routes:
        - to: default
          via: $GATEWAY
      nameservers:
        addresses: [$DNS]
EOT

# Apply the Netplan configuration
netplan apply

echo "Static IP configuration for $IFACE, including DNS, is complete."