Comment 0 for bug 1831787

Netplan config:

network:
  version: 2
  renderer: networkd
  ethernets:
    eno4:
      dhcp4: no
    eno1np0:
      dhcp4: no
      addresses:
        - 172.16.0.2/24
  bridges:
    br0:
      dhcp4: yes
      interfaces:
        - eno4

On initial boot, machine got 10.0.15.109 IP address:

May 03 13:09:41 ceph2 systemd-networkd[29349]: br0: Configured
May 03 13:09:41 ceph2 systemd-networkd[29349]: br0: DHCPv4 address 10.0.15.109/23 via 10.0.15.253

At one point, DHCP server reserver this IP address and client eventually picked up new IP address:

May 03 15:01:12 ceph2 systemd-networkd[1137]: br0: DHCPv4 address 10.0.15.128/23 via 10.0.15.253

This resulted in IP addresses:

# ip -o a
1: lo inet 127.0.0.1/8 scope host lo\ valid_lft forever preferred_lft forever
1: lo inet6 ::1/128 scope host \ valid_lft forever preferred_lft forever
2: eno1np0 inet 172.16.0.2/24 brd 172.16.0.255 scope global eno1np0\ valid_lft forever preferred_lft forever
2: eno1np0 inet6 fe80::b226:28ff:fe53:56be/64 scope link \ valid_lft forever preferred_lft forever
6: br0 inet 10.0.15.128/23 brd 10.0.15.255 scope global dynamic br0\ valid_lft 503sec preferred_lft 503sec
6: br0 inet6 fe80::b8d7:5eff:fe6b:62a/64 scope link \ valid_lft forever preferred_lft forever

So far, everything is fine. But, the routes on the machine are bogus:

# ip r
default via 10.0.15.253 dev br0 proto dhcp src 10.0.15.109 metric 100
default via 10.0.15.253 dev br0 proto dhcp src 10.0.15.128 metric 100
10.0.14.0/23 dev br0 proto kernel scope link src 10.0.15.128
10.0.15.253 dev br0 proto dhcp scope link src 10.0.15.109 metric 100
10.0.15.253 dev br0 proto dhcp scope link src 10.0.15.128 metric 100
172.16.0.0/24 dev eno1np0 proto kernel scope link src 172.16.0.2

routes with src 10.0.15.109 should have been removed when lease was renewed. I'm not sure if this is a bug in netplan or systemd. This is 18.04, systemd 37-3ubuntu10.21, netplan 0.40.1~18.04.4.