netplan cannot set IPv6 token

[Justin Coffman]

Summary:

netplan contains no configuration entry that allows one to statically configure the IPv6 host ID (low 64 bits) when autogenerated (DHCPv6 stateless, SLAAC) addressing is used.

This should map to the IPv6Token entry for systemd-networkd (man systemd.network, [Network] section), and the ipv6.token entry for NetworkManager (https://developer.gnome.org/NetworkManager/stable/settings-ipv6.html).

Release and package data:

> lsb_release -rd
Description: Ubuntu 17.10
Release: 17.10

> apt-cache policy nplan
nplan:
  Installed: 0.30
  Candidate: 0.30
  Version table:
 *** 0.30 500
        500 http://us.archive.ubuntu.com/ubuntu artful/main amd64 Packages
        100 /var/lib/dpkg/status

Expected behavior:

/etc/netplan/01-netcfg.yaml

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    ens3:
      dhcp4: yes
      dhcp6: yes
      ipv6-token: '::2'

# netplan generate
# netplan apply

# ip -6 a (truncated)
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether aa:bb:cc:dd:ee:ff brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.2/24 brd 192.168.1.255 scope global dynamic ens3
       valid_lft 85186sec preferred_lft 85186sec
    inet6 fd6d:beaa:e748:4b87::2/64 scope global mngtmpaddr noprefixroute dynamic
       valid_lft 2591803sec preferred_lft 604603sec
    inet6 fe80::a8bb:ccff:fedd:eeff/64 scope link
       valid_lft forever preferred_lft forever

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Thomas (t.c)]

thats again bad news with netplan :(
really need this!

[Andreas L (avl42)]

Not sure if that applies here, but "fe80::a8bb:ccff:fedd:eeff" is not a valid ipv6 address on this machine.

instead try "fe80::a8bb:ccff:fedd:eeff%ens3"

The problem might be with "systemd-resolved" which happily serves "fe80::a8bb:ccff:fedd:eeff" as an ipv6 address of this machine.

I stumbled over this ticket based on symptoms I saw (unrelated to netplan), and searching for some keywords...

[Lukas Märdian (slyon)]

I proposed a fix for this issue here: https://github.com/CanonicalLtd/netplan/pull/161

[Lukas Märdian (slyon)]

released as of netplan 0.100

[Gary Fowler (alienbabyga)]

Fix appears to only work for single address. When used to add multiple IPv6 token addresses, only the last entry is respected.

Reference bug report: https://bugs.launchpad.net/netplan/+bug/1950130