"Failed to start Raise network interfaces" for bridge br0 even though br0 exists

Question

I have setup two bridge devices on Debian 9.6 box and systemctl status networking.service claims that bridge br1 was not set up, even though after booting it's actually just fine:

% systemctl status networking.service
● networking.service - Raise network interfaces
   Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Sun 2018-12-23 17:27:22 CET; 5min ago
     Docs: man:interfaces(5)
  Process: 591 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)
  Process: 586 ExecStartPre=/bin/sh -c [ "$CONFIGURE_INTERFACES" != "no" ] && [ -n "$(ifquery --read-environment --list --exclude=lo)" ] && udevadm settle (code=exited, status=0/SUCCESS)
 Main PID: 591 (code=exited, status=1/FAILURE)

Dec 23 17:27:21 irys systemd[1]: Starting Raise network interfaces...
Dec 23 17:27:21 irys ifup[591]: Waiting for br1 to get ready (MAXWAIT is 60 seconds).
Dec 23 17:27:22 irys ifup[591]: Waiting for br0 to get ready (MAXWAIT is 60 seconds).
Dec 23 17:27:22 irys ifup[591]: RTNETLINK answers: File exists
Dec 23 17:27:22 irys ifup[591]: ifup: failed to bring up br0
Dec 23 17:27:22 irys systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Dec 23 17:27:22 irys systemd[1]: Failed to start Raise network interfaces.
Dec 23 17:27:22 irys systemd[1]: networking.service: Unit entered failed state.
Dec 23 17:27:22 irys systemd[1]: networking.service: Failed with result 'exit-code'.

After booting:

% brctl show
bridge name bridge id       STP enabled interfaces
br0     8000.00259086c729   no      enp6s0
br1     8000.00259086c728   no      enp5s0

My interfaces setup:

% cat  interfaces

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug enp5s0
allow-hotplug enp6s0

auto br1
iface br1 inet static
    address 192.168.1.212
    netmask 255.255.255.0
    network 192.168.1.0
    broadcast 192.168.1.255
    gateway 192.168.1.254
    dns-search example.com
        bridge_ports enp5s0
        bridge_fd 9
        bridge_hello 2
        bridge_maxage 12
        bridge_stp off
    bridge_maxwait 60

auto br0
iface br0 inet static
    address 10.0.0.9
    netmask 255.0.0.0
    network 10.0.0.0
    broadcast 10.255.255.255
    gateway 10.0.0.254
    dns-search example.com
        bridge_ports enp6s0
        bridge_fd 9
        bridge_hello 2
        bridge_maxage 12
        bridge_stp off

All the networking, services using network work fine.

How do I fix that? I mean, why does systemctl claim that about br0 while bringing up br1 without any problem?

P.S. in journalctl -b output I found this:

Dec 23 17:27:22 irys ifup[591]: Waiting for br0 to get ready (MAXWAIT is 60 seconds).
Dec 23 17:27:22 irys kernel: IPv6: ADDRCONF(NETDEV_UP): br0: link is not ready
Dec 23 17:27:22 irys ifup[591]: RTNETLINK answers: File exists
Dec 23 17:27:22 irys ifup[591]: ifup: failed to bring up br0

Answer 1

You might have to flush br0. This worked for me:

sudo ip addr flush dev br0

Answer 2

Could be related to this bug. My home server is also experiencing similar problem that started a week ago. Which would be strange, because bridge-utils is not updated in Stable for a long time now. What is updated is for example iproute2. I think those packages are closely related and a race condition as explained in the bug would explain the situation.

Answer 3

Removing the duplicate IP address from another interface and then flushing the bridge interface resolved this for me.