0

I am running a centos 8 as virt-host with libvirt an kvm/qemu. Networking is set to bridge-mode with virbr0. Suddenly and over-night this stops working: The clients don't connect anymore, and if I try to connect the network in virtual-machine-manager I get "Bridge virbr0:Empty Bridge" and this even before starting any client.

[root@labpc1 log]# ifconfig
enp5s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.2.8  netmask 255.255.255.0  broadcast 192.168.2.255
        inet6 2003:c0:3713:3000:fa5b:356b:c6a6:18ff  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::9b26:4d1a:f92c:c21c  prefixlen 64  scopeid 0x20<link>
        ether 34:97:f6:8e:c0:73  txqueuelen 1000  (Ethernet)
        RX packets 4788  bytes 482052 (470.7 KiB)
        RX errors 0  dropped 912  overruns 0  frame 0
        TX packets 2205  bytes 617635 (603.1 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.2.8  netmask 255.255.255.0  broadcast 192.168.2.255
        ether de:a2:bd:89:f8:d4  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

There are messages in /var/log/messages:

grep virbr0 /var/log/messages 
Jan  9 19:24:30 labpc1 NetworkManager[1051]: <info>  [1578594270.5088] ifcfg-rh: new connection /etc/sysconfig/network-scripts/ifcfg-virbr0 (a2d02297-f0a1-4f1e-a5c4-ebd5d5e62c89,"virbr0")
Jan  9 19:24:30 labpc1 NetworkManager[1051]: <info>  [1578594270.5092] ifcfg-rh: new connection /etc/sysconfig/network-scripts/ifcfg-virbr0_slave_1 (7b0e15aa-3c0c-44a6-802e-0a1af319a2e2,"virbr0 slave 1")
Jan  9 19:24:31 labpc1 NetworkManager[1051]: <info>  [1578594271.2427] manager: (virbr0): new Bridge device (/org/freedesktop/NetworkManager/Devices/3)
Jan  9 19:24:31 labpc1 systemd-udevd[1340]: Could not generate persistent MAC address for virbr0: No such file or directory
Jan  9 19:24:31 labpc1 kernel: IPv6: ADDRCONF(NETDEV_UP): virbr0: link is not ready
Jan  9 19:24:31 labpc1 NetworkManager[1051]: <info>  [1578594271.4417] device (virbr0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Jan  9 19:24:31 labpc1 NetworkManager[1051]: <info>  [1578594271.4439] device (virbr0): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed')
Jan  9 19:24:31 labpc1 NetworkManager[1051]: <info>  [1578594271.4449] policy: auto-activating connection 'virbr0' (a2d02297-f0a1-4f1e-a5c4-ebd5d5e62c89)
Jan  9 19:24:31 labpc1 NetworkManager[1051]: <info>  [1578594271.4455] device (virbr0): Activation: starting connection 'virbr0' (a2d02297-f0a1-4f1e-a5c4-ebd5d5e62c89)
Jan  9 19:24:31 labpc1 NetworkManager[1051]: <info>  [1578594271.4456] device (virbr0): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed')
Jan  9 19:24:31 labpc1 NetworkManager[1051]: <info>  [1578594271.4543] device (virbr0): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Jan  9 19:24:32 labpc1 NetworkManager[1051]: <info>  [1578594272.7065] device (virbr0): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed')
Jan  9 19:24:32 labpc1 NetworkManager[1051]: <info>  [1578594272.7077] device (virbr0): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'managed')
Jan  9 19:24:32 labpc1 kernel: IPv6: ADDRCONF(NETDEV_UP): virbr0: link is not ready
Jan  9 19:24:32 labpc1 avahi-daemon[932]: Joining mDNS multicast group on interface virbr0.IPv4 with address 192.168.2.8.
Jan  9 19:24:32 labpc1 NetworkManager[1051]: <info>  [1578594272.7083] device (virbr0): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'managed')
Jan  9 19:24:32 labpc1 avahi-daemon[932]: New relevant interface virbr0.IPv4 for mDNS.
Jan  9 19:24:32 labpc1 NetworkManager[1051]: <info>  [1578594272.7084] device (virbr0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'managed')
Jan  9 19:24:32 labpc1 avahi-daemon[932]: Registering new address record for 192.168.2.8 on virbr0.IPv4.
Jan  9 19:24:32 labpc1 NetworkManager[1051]: <info>  [1578594272.8032] policy: set 'virbr0' (virbr0) as default for IPv4 routing and DNS
Jan  9 19:24:32 labpc1 NetworkManager[1051]: <info>  [1578594272.8863] device (virbr0): Activation: successful, device activated.
Jan  9 19:24:32 labpc1 nm-dispatcher[1121]: req:3 'up' [virbr0]: new request (3 scripts)
Jan  9 19:24:32 labpc1 nm-dispatcher[1121]: req:3 'up' [virbr0]: start running ordered scripts...

Most specifically I am missing a message like kernel: virbr0: port 3(vnet1) entered forwarding state

It used to work without any deliberate change ..

Any hint would be highly appreciated

Wolfgang

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.