Ubuntu Server 20.04 set static IP with netplan

First check if you have file

/etc/cloud/cloud.cfg.d/subiquity-disable-cloudinit-networking.cfg

If the file exists, make sure, you have the following content in it.

root@ubuntu:~# cat /etc/cloud/cloud.cfg.d/subiquity-disable-cloudinit-networking.cfg
network: {config: disabled}
root@ubuntu:~# 

Edit

vi /etc/netplan/00-installer-config.yaml

Replace all content with

network:
    version: 2
    ethernets:
        eth0:
            addresses: [192.168.1.100/24]
            routes:
                - to: default
                  via: 192.168.1.1
            nameservers:
                addresses: [1.1.1.1, 8.8.8.8]

In the above cause 192.168.1.100 is your static IP address. 192.168.1.1 is the gateway. eth0 is the network interface name.

Older versions of netpan used gateway4 instead of routes.

            gateway4: 192.168.1.1

Now try the changes with

netplan try

If all is good, you can make changes permanent with

netplan apply

See IP