Set static IP on Ubuntu 16.04

open file

# vi /etc/network/interfaces

Below is my default contents

# The primary network interface
auto enp0s3
iface enp0s3 inet dhcp

change to static address

# The primary network interface
auto enp0s3
iface enp0s3 inet static
address xxx.xxx.xxx.xxx
netmask xxx.xxx.xxx.xxx
gateway xxx.xxx.xxx.xxx
dns-nameservers xxx.xxx.xxx.xxx

network restart

# systemctl restart networking.service