# UPDATE: for newer systems better directly use:
# vim /etc/dhcpcd.conf:
#
# interface eth0
# static ip_address=192.168.1.150/24
# static routers=192.168.1.1
# static domain_name_servers=192.168.1.1
#
# now reboot the rpi


# static ip configuration
# /etc/netplan/50-cloud-init.yaml

network:
    ethernets:
        eth0:
            dhcp4: true
            optional: true
    wifis:
        wlan0:
            dhcp4: no
            dhcp6: no
            addresses: [192.168.1.150/24]
            gateway4: 192.168.1.1
            nameservers:
                addresses: [1.1.1.1, 8.8.8.8]
            access-points:
                "wifiname":
                    password: "password"
    version: 2