Comment 21 for bug 1959570

I tested netplan.io 0.104-0ubuntu2~20.04.4 from focal-proposed, TestCase2 "Classic". Everything worked as expected, no crashes observed. Also the new "test_try_accept_lp1959570" autopkgtest PASSed on all architectures.

root@ff-sru:~# dpkg -l | grep netplan
ii libnetplan0:amd64 0.104-0ubuntu2~20.04.4 amd64
ii netplan.io 0.104-0ubuntu2~20.04.4 amd64

root@ff-sru:~# apt install network-manager
root@ff-sru:~# mv /usr/bin/nmcli /snap/bin/nmcli
root@ff-sru:~# netplan get [16/358]
network:
  version: 2
  ethernets:
    eth0:
      dhcp4: true
root@ff-sru:~# netplan set network.renderer=NetworkManager # change global renderer to NM
root@ff-sru:~# netplan set network.bridges.br54.addresses=[10.0.0.20/24]
root@ff-sru:~# netplan get
network:
  version: 2
  renderer: NetworkManager
  ethernets:
    eth0:
      dhcp4: true
  bridges:
    br54:
      addresses:
      - "10.0.0.20/24"
root@ff-sru:~# env -u PATH /usr/sbin/netplan try # Try-Apply the configuration
Do you want to keep these settings?

Press ENTER before the timeout to accept the new configuration

Changes will revert in 115 seconds
Configuration accepted.
root@ff-sru:~# /snap/bin/nmcli d show br54
GENERAL.DEVICE: br54
GENERAL.TYPE: bridge
GENERAL.HWADDR: AE:E7:C5:00:4C:D2
GENERAL.MTU: 1500
GENERAL.STATE: 100 (connected)
GENERAL.CONNECTION: netplan-br54
GENERAL.CON-PATH: /org/freedesktop/NetworkManager/ActiveConnection/2
IP4.ADDRESS[1]: 10.0.0.20/24
IP4.GATEWAY: --
IP4.ROUTE[1]: dst = 10.0.0.0/24, nh = 0.0.0.0, mt = 425
root@ff-sru:~# ip addr show br54
2: br54: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether ae:e7:c5:00:4c:d2 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.20/24 brd 10.0.0.255 scope global noprefixroute br54
       valid_lft forever preferred_lft forever

root@ff-sru:~# killall netplan-dbus
netplan-dbus: no process found
root@ff-sru:~# env -u PATH /usr/lib/netplan/netplan-dbus &
[1] 2844
root@ff-sru:~# busctl call io.netplan.Netplan /io/netplan/Netplan io.netplan.Netplan Config
o "/io/netplan/Netplan/config/CFHCE2"
root@ff-sru:~# busctl call io.netplan.Netplan /io/netplan/Netplan/config/CFHCE2 io.netplan.Netplan.Config Try u 120
b true
root@ff-sru:~# busctl call io.netplan.Netplan /io/netplan/Netplan/config/CFHCE2 io.netplan.Netplan.Config Apply
b true
root@ff-sru:~# fg
env -u PATH /usr/lib/netplan/netplan-dbus
^C