[SOLVED] Cant start KVM when bridged network device added

[benleb]

Hey,

I'm running a proxmox 4 server with a few lxc servers. today I tried to add a KVM but I can't start it when a bridged network device is attached. when I change to nat, the VM starts.

I tried e1000, virtio, all bridges available on this server... nothing works and I can't get a helpful error message.

Error

(14:06:22) prox1 ~ # qm start 109
Running as unit 109.scope.
kvm: -netdev type=tap,id=net0,ifname=tap109i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on: could not open /dev/net/tun: No such file or directory
start failed: command '/usr/bin/systemd-run --scope --slice qemu --unit 109 -p 'KillMode=none' -p 'CPUShares=1000' /usr/bin/kvm -id 109 -chardev 'socket,id=qmp,path=/var/run/qemu-server/109.qmp,server,nowait' -mon 'chardev=qmp,mode=control' -pidfile /var/run/qemu-server/109.pid -daemonize -smbios 'type=1,uuid=58a1de51-2f08-4e97-92ea-bd7960cc1650' -name perth -smp '2,sockets=1,cores=2,maxcpus=2' -nodefaults -boot 'menu=on,strict=on,reboot-timeout=1000' -vga std -vnc unix:/var/run/qemu-server/109.vnc,x509,password -no-hpet -cpu 'kvm64,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv_relaxed,+lahf_lm,+sep,+kvm_pv_unhalt,+kvm_pv_eoi,enforce' -m 2048 -k de -device 'pci-bridge,id=pci.1,chassis_nr=1,bus=pci.0,addr=0x1e' -device 'pci-bridge,id=pci.2,chassis_nr=2,bus=pci.0,addr=0x1f' -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' -device 'usb-tablet,id=tablet,bus=uhci.0,port=1' -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' -iscsi 'initiator-name=iqn.1993-08.org.debian:01:6d745c7a855' -drive 'if=none,id=drive-ide2,media=cdrom,aio=threads' -device 'ide-cd,bus=ide.1,unit=0,drive=drive-ide2,id=ide2,bootindex=200' -device 'ahci,id=ahci0,multifunction=on,bus=pci.0,addr=0x7' -drive 'file=/dev/pve/vm-109-disk-1,if=none,id=drive-sata0,format=raw,cache=none,aio=native,detect-zeroes=on' -device 'ide-drive,bus=ahci0.0,drive=drive-sata0,id=sata0,bootindex=100' -netdev 'type=tap,id=net0,ifname=tap109i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' -device 'virtio-net-pci,mac=66:62:65:32:33:38,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' -rtc 'driftfix=slew,base=localtime' -global 'kvm-pit.lost_tick_policy=discard'' failed: exit code 1

Versions

(14:12:12) prox1 ~ # pveversion --verbose
proxmox-ve: 4.2-48 (running kernel: 4.4.6-1-pve)
pve-manager: 4.2-2 (running version: 4.2-2/725d76f0)
pve-kernel-4.4.6-1-pve: 4.4.6-48
lvm2: 2.02.116-pve2
corosync-pve: 2.3.5-2
libqb0: 1.0-1
pve-cluster: 4.0-39
qemu-server: 4.0-72
pve-firmware: 1.1-8
libpve-common-perl: 4.0-59
libpve-access-control: 4.0-16
libpve-storage-perl: 4.0-50
pve-libspice-server1: 0.12.5-2
vncterm: 1.2-1
pve-qemu-kvm: 2.5-14
pve-container: 1.0-62
pve-firewall: 2.0-25
pve-ha-manager: 1.0-28
ksm-control-daemon: 1.2-1
glusterfs-client: 3.5.2-2+deb8u1
lxc-pve: 1.1.5-7
lxcfs: 2.0.0-pve2
cgmanager: 0.39-pve1
criu: 1.6.0-1
zfsutils: 0.6.5-pve9~jessie

System report (network part):

==== info about network and firewall ====
# ifconfig
eth0      Link encap:Ethernet  HWaddr 24:b6:fd:f8:c7:e0 
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:428964202 errors:0 dropped:5 overruns:0 frame:0
          TX packets:3692216909 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:69819847482 (65.0 GiB)  TX bytes:5515447931199 (5.0 TiB)
          Interrupt:39

eth1      Link encap:Ethernet  HWaddr 24:b6:fd:f8:c7:e1 
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:65179455 errors:0 dropped:0 overruns:0 frame:0
          TX packets:75612915 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:20492607441 (19.0 GiB)  TX bytes:47598088488 (44.3 GiB)
          Interrupt:40

eth3      Link encap:Ethernet  HWaddr 24:b6:fd:f8:c7:e3 
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2170448 errors:2 dropped:0 overruns:0 frame:1
          TX packets:38458 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:342764719 (326.8 MiB)  TX bytes:14564109 (13.8 MiB)
          Interrupt:42

vmbr0     Link encap:Ethernet  HWaddr 24:b6:fd:f8:c7:e0 
          inet addr:10.11.2.101  Bcast:10.11.2.255  Mask:255.255.255.0
          inet6 addr: fe80::26b6:fdff:fef8:c7e0/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:410448747 errors:0 dropped:0 overruns:0 frame:0
          TX packets:185587026 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:61135464888 (56.9 GiB)  TX bytes:5269212906793 (4.7 TiB)

vmbr1     Link encap:Ethernet  HWaddr 24:b6:fd:f8:c7:e1 
          inet6 addr: fe80::26b6:fdff:fef8:c7e1/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:11226850 errors:0 dropped:4226 overruns:0 frame:0
          TX packets:17 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:729111747 (695.3 MiB)  TX bytes:1486 (1.4 KiB)

vmbr3     Link encap:Ethernet  HWaddr 24:b6:fd:f8:c7:e3 
          inet addr:192.168.178.10  Bcast:192.168.178.255  Mask:255.255.255.0
          inet6 addr: fe80::26b6:fdff:fef8:c7e3/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1683926 errors:0 dropped:1993 overruns:0 frame:0
          TX packets:34815 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:169025135 (161.1 MiB)  TX bytes:14160049 (13.5 MiB)

# cat /etc/network/interfaces
# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage part of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

auto lo
iface lo inet loopback

iface eth0 inet manual

iface eth1 inet manual

iface eth2 inet manual

iface eth3 inet manual

auto vmbr0
iface vmbr0 inet static
    address  10.11.2.101
    netmask  255.255.255.0
    gateway  10.11.2.1
    bridge_ports eth0
    bridge_stp off
    bridge_fd 0

auto vmbr1
iface vmbr1 inet manual
    bridge_ports eth1
    bridge_stp off
    bridge_fd 0

auto vmbr3
iface vmbr3 inet static
    address  192.168.178.10
    netmask  255.255.255.0
    bridge_ports eth3
    bridge_stp off
    bridge_fd 0

Any ideas how to solve this? Where is the problem? More info needed?

Thank you!

Ben

 

[dietmar]

the following looks strange: "could not open /dev/net/tun: No such file or directory"

Does it help if you reboot that node?

 

[wbumiller]

The tun/tap driver should be compiled in though, so maybe it's enough to `mknod /dev/net/tun c 10 200`, but why would the node be gone?

 

[benleb]

Okay, solved by rebooting. But as this is a production node, this wasnt a really good option.

Thank you!