Netplan

config

# /etc/netplan/01-netcfg.yaml
network:
  ethernets:
    ens18:
      dhcp4: true
  version: 2

-

sudo netplan apply

Debug plan:

sudo netplan --debug apply
  # note "apply --debug" does not work

-

# networkctl
IDX LINK  TYPE     OPERATIONAL SETUP
  1 lo    loopback carrier     unmanaged
  2 ens18 ether    routable    configured

2 links listed.

-

Ubuntu to regen machine-id

rm -f /etc/machine-id /var/lib/dbus/machine-id
# dbus-uuidgen --ensure=/etc/machine-id
dbus-uuidgen --ensure
#cp /var/lib/dbus/machine-id /etc/machine-id
systemd-machine-id-setup
# verify:
cat /etc/machine-id /var/lib/dbus/machine-id
hostnamectl

examples

https://github.com/canonical/netplan/tree/main/examples

static

network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      addresses:
        - 10.10.10.2/24
      nameservers:
        search: [mydomain, otherdomain]
        addresses: [10.10.10.1, 1.1.1.1]
      routes: 
        - to: default
          via: 10.10.10.1

ref: https://github.com/canonical/netplan/blob/main/examples/static.yaml

dhcp

network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      dhcp4: true

ref: https://github.com/canonical/netplan/blob/main/examples/dhcp.yaml

vlan

network:
    version: 2
    ethernets:
        eno1:
            ... eno1 config ...
    vlans:
        vlan100:
            id: 100
            link: eno1
            addresses: [10.0.0.100/24]
            # dhcp4: true

Renderer

Warning: If both systemd-networkd and NetworkManager are active on the same interface, conflicts may occur. The renderer setting ensures control is delegated correctly.

networkd

network:
  version: 2
  renderer: networkd

NetworkManager

This system is being managed by NetworkManager.

Default:

# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager

More:

# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager
  ethernets:
    enp3s0:
      dhcp4: true

Apply configuration:

sudo netplan apply

Verify backend:

nmcli device status

Warning: If both systemd-networkd and NetworkManager are active on the same interface, conflicts may occur. The renderer setting ensures control is delegated correctly.