networkd-dispatcher wifi/ethernet switchover

gistfile1.txt

##
#/etc/networkd-dispatcher/no-carrier.d/50-ifdown-hooks
##

#!/bin/bash
enable_disable_wifi ()
{
    if [ "$IFACE" == "enp0s25" ]; then
       echo "$(date) - $IFACE down wifi unblocked"
       rfkill unblock wifi
    fi
}

enable_disable_wifi

##
#/etc/networkd-dispatcher/routable.d/50-ifup-hooks
##
#!/bin/bash
enable_disable_wifi ()
{
    if [ "$IFACE" == "enp0s25" ]; then
       echo "$(date) - $IFACE up wifi blocked"
       rfkill block wifi
    fi
}
enable_disable_wifi

##
#  /etc/netplan/00-installer-config.yaml
#  enp0s25 has a static DHCP assignment (192.168.0.110)
#  wifi manually assigns the same IP
##

# This is the network config written by 'subiquity'
network:
  ethernets:
    enp0s25:
      dhcp4: true
      optional: true
  version: 2
  wifis:
    wlp3s0:
      optional: true
      access-points:
        "BSSID":
          password: "PASSWORD"
      dhcp4: no
      addresses:
        - 192.168.0.110/24
      routes:
        - to: default
          via: 192.168.0.1
      nameservers:
        addresses: [192.168.0.1]

Remember to netplan apply and systemctl enable networkd-dispatcher and systemctl restart networkd-dispatcher to reload the scripts.