Comment 22 for bug 2036358

I have verified the fix using systemd 249.11-0ubuntu3.11 from jammy-proposed:

Creating a fresh container:

nr@six:~$ lxc launch ubuntu-daily:jammy jammy
Creating jammy
Starting jammy
nr@six:~$ lxc exec jammy bash

Within the container, after enabling -proposed:

root@jammy:~# vi /etc/apt/sources.list
root@jammy:~# apt update && apt install systemd -y
[ ... ]
root@jammy:~# apt-cache policy systemd
systemd:
  Installed: 249.11-0ubuntu3.11
  Candidate: 249.11-0ubuntu3.11
  Version table:
 *** 249.11-0ubuntu3.11 500
        500 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     249.11-0ubuntu3.10 500
        500 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages
     249.11-0ubuntu3.7 500
        500 http://security.ubuntu.com/ubuntu jammy-security/main amd64 Packages
     249.11-0ubuntu3 500
        500 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages
root@jammy:~# vi /etc/netplan/50-cloud-init.yaml
root@jammy:~# cat /etc/netplan/50-cloud-init.yaml
# This file is generated from information provided by the datasource. Changes
# to it will not persist across an instance reboot. To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    version: 2
    ethernets:
        eth0:
            dhcp4: true
            optional: true
root@jammy:~# netplan generate
root@jammy:~# netplan apply
root@jammy:~# time SYSTEMD_LOG_LEVEL=debug /lib/systemd/systemd-networkd-wait-online --timeout=5
Found link 11
Found link 1
eth0: link is ignored
lo: link is ignored

real 0m0.004s
user 0m0.003s
sys 0m0.000s
root@jammy:~# echo $?
0

I also ran the test from bug 1982218 again to ensure that does not regress:

On the host, I have clean-jammy-amd64, and detached it's default network interface:

nr@six:~$ virsh detach-interface clean-jammy-amd64 network
Interface detached successfully

Then, in the VM, configure systemd-networkd to use DHCP on all en* interfaces:

nr@clean-jammy-amd64:~$ apt-cache policy systemd
systemd:
  Installed: 249.11-0ubuntu3.11
  Candidate: 249.11-0ubuntu3.11
  Version table:
 *** 249.11-0ubuntu3.11 500
        500 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     249.11-0ubuntu3.10 500
        500 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages
     249.11-0ubuntu3.7 500
        500 http://security.ubuntu.com/ubuntu jammy-security/main amd64 Packages
     249.11-0ubuntu3 500
        500 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages
nr@clean-jammy-amd64:~$ sudo su
root@clean-jammy-amd64:/home/nr# cat > /etc/systemd/network/10-dhcp.network << EOF
[Match]
Name=en*

[Network]
DHCP=yes
EOF
root@clean-jammy-amd64:/home/nr# systemctl restart systemd-networkd

Now, back in the host, I attach a network interface without DHCP:

nr@six:~$ virsh attach-interface clean-jammy-amd64 network no-dhcp
Interface attached successfully

In the VM, check that wait-online times out since the interface does not get configured:

root@clean-jammy-amd64:/home/nr# /lib/systemd/systemd-networkd-wait-online --any --timeout=5
Timeout occurred while waiting for network connectivity.
root@clean-jammy-amd64:/home/nr# networkctl
IDX LINK TYPE OPERATIONAL SETUP
  1 lo loopback carrier unmanaged
  3 ens3 ether degraded configuring

2 links listed.

From the host, attach another interface that will get DHCP:

nr@six:~$ virsh attach-interface clean-jammy-amd64 network default
Interface attached successfully

And finally, in the VM, run wait-online again and see that it will exit successfully when the second interface is configured:

root@clean-jammy-amd64:/home/nr# /lib/systemd/systemd-networkd-wait-online --any --timeout=0
root@clean-jammy-amd64:/home/nr# networkctl
IDX LINK TYPE OPERATIONAL SETUP
  1 lo loopback carrier unmanaged
  3 ens3 ether degraded configuring
  4 ens9 ether routable configured

3 links listed.