Ubuntu Server Headless Boot + Configuration

I recently built a Z270 + 1240v6 system and planned to run it headless (without even a graphics card!). However, I ran into issues - after removing the graphics card, the network failed and the CPU fan ran slowly.

I thought a kernel module crash caused a kernel panic and spent hours troubleshooting. Finally, I found this blog post and discovered the issue was PCIE changes causing the network interface name to change. So I modified netplan to:

network:
  version: 2
  ethernets:
    enp1s0:
      dhcp4: true
    enp2s0:
      dhcp4: true
    enp3s0:
      dhcp4: true
    enp4s0:
      dhcp4: true
    enp5s0:
      dhcp4: true

Restarting solved the issue! After logging in, I found it was now running on enp1s0!

Edit: You can actually use netplan's MAC match feature to specify the interface, which effectively solves these issues.

---

Final Configuration

netplan:

network:
  version: 2
  ethernets:
    onboardeth:
      match:
        macaddress: aa:bb:cc:dd:ee:ff
      dhcp4: false
      addresses:
        - 192.168.1.x/24
        - 192.168.8.x/24
      routes:
        - to: default
          via: 192.168.1.1
        - to: 192.168.255.y/25
          via: 192.168.8.z
      nameservers:
        addresses:
          - 192.168.1.1

/etc/udev/rules.d/99-usb-serial-getty.rules:

ACTION=="add", SUBSYSTEM=="tty", ATTRS{idVendor}=="1a86", ATTRS{idProduct}=="7523", RUN+="/usr/bin/stty -F /dev/%k 115200", TAG+="systemd", ENV{SYSTEMD_WANTS}="serial-getty@%k.service"

lxd + vxlan isolated network configuration:

https://artivis.github.io/post/2024/lxc-isolated/

name: lxdbr2
description: ipv4 only internet isolated
type: bridge
config:
  security.acls: external-only
  security.acls.default.egress.action: allow
  security.acls.default.ingress.action: allow
  ipv4.address: 10.122.156.1/24
  ipv4.nat: 'true'
  ipv6.address: none

name: lxdbr1
description: vxlan to global v6
type: bridge
config:
  tunnel.lxdv6.id: 'abcd'
  tunnel.lxdv6.interface: enp3s0
  tunnel.lxdv6.local: 192.168.8.x
  tunnel.lxdv6.port: '4789'
  tunnel.lxdv6.protocol: vxlan
  tunnel.lxdv6.remote: 192.168.8.z
  ipv4.address: none
  ipv6.address: none

/etc/systemd/system/wol.service:

[Unit]
Description=Enable Wake On Lan
 
[Service]
Type=oneshot
#ExecStart=/bin/bash -c 'for a in {1..9}; do echo /usr/sbin/ethtool --change enp"${a}"s0 wol g || true; done'
ExecStart=/etc/initwol.sh


[Install]
WantedBy=basic.target

Useful commands:

systemctl enable serial-getty@ttyUSBx