netplan networkd - bridge configuration not work

[Alexey Smovzh]

Ubuntu: 18.04.3 LTS bionic

Kernel: 4.15.0-70-generic

1. configure network bridge with brctl with following commands and all works fine:

sudo brctl addbr br-ex
sudo brctl addif br-ex enp0s3
sudo ip link set mtu 1500 dev br-ex
sudo ip addr del 10.64.10.100/24 brd 10.64.10.255 dev enp0s3
sudo ip addr replace 10.64.10.100/24 brd 10.64.10.255 dev br-ex
sudo ip link set br-ex up
sudo ip -f inet r replace default via 10.64.10.1 dev br-ex

2. configure the same network bridge with netplan and NetworkManager as renderer with following config all works fine:

network:
  version: 2
  renderer: NetworkManager
  ethernets:
    enp0s3:
      dhcp4: no
      dhcp6: no
  bridges:
    br-ex:
      interfaces: [enp0s3]
      addresses: [10.64.10.100/24]
      gateway4: 10.64.10.1
      mtu: 1500
      nameservers:
        addresses: [8.8.8.8]
      dhcp4: no
      dhcp6: no
      parameters:
        stp: no

3. Configure network bridge with same config but with networkd as network renderer does not work
networkctl - shows that interfaces are managed by networkd and its ok
ip a - shows proper bridge configuration and ip address assignment
ip route - shows proper route via 10.64.10.1 and br-ex dev
No any error messages in systemd-networkd service log
But network don't work
I can't ping external hosts from this machine or ping this machine from external host

  network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s3:
      dhcp4: no
      dhcp6: no
  bridges:
    br-ex:
      interfaces: [enp0s3]
      addresses: [10.64.10.100/24]
      gateway4: 10.64.10.1
      mtu: 1500
      nameservers:
        addresses: [8.8.8.8]
      dhcp4: no
      dhcp6: no
      parameters:
        stp: no

Can it be that i mislead some required by networkd configuration parameter?
Or may be networkd does not set some kernel parameter which brctl and NetworkManager does?

[Ubuntu Foundations Team Bug Bot (crichton)]

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[Alexey Smovzh (alexeysmovzh)]

In systemd-networkd documentation found that networkd assign different MAC address to the bridge than physical interface has and this my lead to some connection issues. To avoid this problems you must specify MAC address to bridge interface same as on your physical device.
After I add proper MAC address to bridge interface configuration start working.

New working config:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s3:
      dhcp4: no
      dhcp6: no
  bridges:
    br-ex:
      macaddress: 08:00:27:0b:07:94
      interfaces: [enp0s3]
      addresses: [10.64.10.100/24]
      gateway4: 10.64.10.1
      mtu: 1500
      nameservers:
        addresses: [8.8.8.8]
      dhcp4: no
      dhcp6: no
      parameters:
        stp: no

I suggest this MAC address issue should be mentioned in Netplan documentation.
Particular in examples page (https://netplan.io/examples) because it appear as first result when googling how to configure network with netplan.

[Launchpad Janitor (janitor)]

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