systemd-networkd: default to DUIDType=link-layer for ipv6; via networkd.conf.d

[rpardini]

systemd-networkd: default to DUIDType=link-layer for ipv6; via networkd.conf.d

• systemd-networkd: default to DUIDType=link-layer for ipv6; via networkd.conf.d
  • only affects systemd-networkd-using builds (MINIMAL images?)
  • does NOT affect NetworkManager
  • this allows network administrators to give out IPv6 addresses over DHCPv6 based on the MAC address (which should be stable) instead of systemd's own notion of it's "DUID", which is based on the machine-id and changes on every redeployment

[igorpecovnik]

Would adding dhcp-identifier: "mac" do the same? Netplan example (but in ipv4 configuration):

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      addresses:
      - "10.0.10.229/24"
      nameservers:
        addresses:
        - 9.9.9.9
        - 1.1.1.1
      dhcp-identifier: "mac"
      routes:
      - metric: 200
        to: "0.0.0.0/0"
        via: "10.0.10.1"

[rpardini]

Would adding dhcp-identifier: "mac" do the same? Netplan

I've stumbled upon that, but I'm unsure what it really does and it seems it depends on the netplan version. Either way, doing it in netplan would (possibly) affect NetworkManager as well, while requiring all netplan configurations to have it. Doing it at the systemd-networkd level makes it consistent independent of the netplan config.

As you can probably guess, this is specially important for cloud images, which may generate their own netplan config based on the c-i metadata.

[igorpecovnik]

affect NetworkManager as well

AFAIK this feature is not supported by NM anyway. At least not NetPlan way.

OK, I think its better to have this then not have it or leave user to depend on setting dhcp-identifier and hope being properly translated.