[Bug 997978] Re: KVM images lose connectivity with bridged network

Georg Leciejewski vespaschorsch at gmx.de
Tue Jun 12 12:58:33 UTC 2012


@serge, thanks for your input. here Dom0 ifconfig, with 2 machines
running.

i setup br0 myself because the machines are running at hetzner, with
special addon IP's so the vm's can be reached from the outside.
(wiki.hetzner.de/index.php/KVM_mit_Nutzung_aller_IPs_-_the_easy_way) i
am also evaluating the problem with hetzner support to ensure its not
one of their routers in from of the Dom0.

vnet0, vnet1 are the bridges created by libvirt, but the vm have static
ip entries in /network/interfaces and are bound to br0 via libvirt.

------------------------------

br0       Link encap:Ethernet  HWaddr c8:60:00:e9:4a:2e  
          inet addr:176.9.126.xx  Bcast:0.0.0.0  Mask:255.255.255.255
          inet6 addr: fe80::ca60:ff:fee9:4a2e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5852477 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4403013 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:2310013511 (2.3 GB)  TX bytes:2588138678 (2.5 GB)

eth0      Link encap:Ethernet  HWaddr c8:60:00:e9:4a:2e  
          inet addr:176.9.126.xx  Bcast:176.9.126.95  Mask:255.255.255.192
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:6623242 errors:0 dropped:35190 overruns:0 frame:0
          TX packets:4668377 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2484375973 (2.4 GB)  TX bytes:1715146205 (1.7 GB)
          Interrupt:17 Memory:fe500000-fe520000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:59917 errors:0 dropped:0 overruns:0 frame:0
          TX packets:59917 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:9106822 (9.1 MB)  TX bytes:9106822 (9.1 MB)

vnet0     Link encap:Ethernet  HWaddr fe:54:00:2e:3d:0e  
          inet6 addr: fe80::fc54:ff:fe2e:3d0e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2033457 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2971987 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500 
          RX bytes:1023321831 (1.0 GB)  TX bytes:1482597549 (1.4 GB)

vnet1     Link encap:Ethernet  HWaddr fe:54:00:3f:2a:9c  
          inet6 addr: fe80::fc54:ff:fe3f:2a9c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:124034 errors:0 dropped:0 overruns:0 frame:0
          TX packets:140178 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500 
          RX bytes:27970351 (27.9 MB)  TX bytes:56681695 (56.6 MB)
------------------------------------

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https://bugs.launchpad.net/bugs/997978

Title:
  KVM images lose connectivity with bridged network

Status in “bridge-utils” package in Ubuntu:
  Invalid
Status in “libvirt” package in Ubuntu:
  Incomplete
Status in “qemu-kvm” package in Ubuntu:
  Confirmed

Bug description:
  System:
  -----------
  Dell R410 Dual processor 2.4Ghz w/16G RAM
  Distributor ID: Ubuntu
  Description:    Ubuntu 12.04 LTS
  Release:        12.04
  Codename:       precise

  Setup:
  ---------
  We're running 3 KVM guests, all Ubuntu 12.04 LTS using bridged networking. 

  From the host:
  # cat /etc/network/interfaces
  auto br0
  iface br0 inet static
          address 212.XX.239.98
          netmask 255.255.255.240
          gateway 212.XX.239.97
          bridge_ports eth0
          bridge_fd 9
          bridge_hello 2
          bridge_maxage 12
          bridge_stp off

  # ifconfig eth0
  eth0      Link encap:Ethernet  HWaddr d4:ae:52:84:2d:5a  
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:11278363 errors:0 dropped:3128 overruns:0 frame:0
            TX packets:14437384 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:4115980743 (4.1 GB)  TX bytes:5451961979 (5.4 GB)
            Interrupt:36 Memory:da000000-da012800 

  # ifconfig br0
  br0       Link encap:Ethernet  HWaddr d4:ae:52:84:2d:5a  
            inet addr:212.XX.239.98  Bcast:212.XX.239.111  Mask:255.255.255.240
            inet6 addr: fe80::d6ae:52ff:fe84:2d5a/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:1720861 errors:0 dropped:0 overruns:0 frame:0
            TX packets:1708622 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0 
            RX bytes:210152198 (210.1 MB)  TX bytes:300858508 (300.8 MB)

  # brctl show
  bridge name     bridge id               STP enabled     interfaces
  br0             8000.d4ae52842d5a       no              eth0

  I have no default network configured to autostart in libvirt as we're using bridged networking:
  # virsh net-list --all
  Name                 State      Autostart
  -----------------------------------------
  default              inactive   no        

  # arp
  Address                  HWtype  HWaddress           Flags Mask            Iface
  mailer03.xxxx.com       ether   52:54:00:82:5f:0f   C                     br0
  mailer01.xxxx.com       ether   52:54:00:d2:f7:31   C                     br0
  mailer02.xxxx.com       ether   52:54:00:d3:8f:91   C                     br0
  dxi-gw2.xxxx.com        ether   00:1a:30:2a:b1:c0   C                     br0

  From one of the guests:
  <domain type='kvm' id='4'>
    <name>mailer01</name>
    <uuid>d41d1355-84e8-ae23-e84e-227bc0231b97</uuid>
    <memory>2097152</memory>
    <currentMemory>2097152</currentMemory>
    <vcpu>1</vcpu>
    <os>
      <type arch='x86_64' machine='pc-1.0'>hvm</type>
      <boot dev='hd'/>
    </os>
    <features>
      <acpi/>
    </features>
    <clock offset='utc'/>
    <on_poweroff>destroy</on_poweroff>
    <on_reboot>restart</on_reboot>
    <on_crash>destroy</on_crash>
    <devices>
      <emulator>/usr/bin/kvm</emulator>
      <disk type='file' device='disk'>
        <driver name='qemu' type='raw'/>
        <source file='/dev/mapper/vg_main-mailer01--root'/>
        <target dev='hda' bus='ide'/>
        <alias name='ide0-0-0'/>
        <address type='drive' controller='0' bus='0' unit='0'/>
      </disk>
      <disk type='file' device='disk'>
        <driver name='qemu' type='raw'/>
        <source file='/dev/mapper/vg_main-mailer01--swap'/>
        <target dev='hdb' bus='ide'/>
        <alias name='ide0-0-1'/>
        <address type='drive' controller='0' bus='0' unit='1'/>
      </disk>
      <controller type='ide' index='0'>
        <alias name='ide0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
      </controller>
      <interface type='bridge'>
        <mac address='52:54:00:d2:f7:31'/>
        <source bridge='br0'/>
        <target dev='vnet0'/>
        <model type='virtio'/>
        <alias name='net0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
      </interface>
      <serial type='pty'>
        <source path='/dev/pts/0'/>
        <target port='0'/>
        <alias name='serial0'/>
      </serial>
      <console type='pty' tty='/dev/pts/0'>
        <source path='/dev/pts/0'/>
        <target type='serial' port='0'/>
        <alias name='serial0'/>
      </console>
      <input type='mouse' bus='ps2'/>
      <graphics type='vnc' port='5900' autoport='yes' listen='127.0.0.1'>
        <listen type='address' address='127.0.0.1'/>
      </graphics>
      <video>
        <model type='cirrus' vram='9216' heads='1'/>
        <alias name='video0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
      </video>
      <memballoon model='virtio'>
        <alias name='balloon0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
      </memballoon>
    </devices>
    <seclabel type='dynamic' model='apparmor' relabel='yes'>
      <label>libvirt-d41d1355-84e8-ae23-e84e-227bc0231b97</label>
      <imagelabel>libvirt-d41d1355-84e8-ae23-e84e-227bc0231b97</imagelabel>
    </seclabel>
  </domain>

  From within the guest:
  # cat /etc/network/interfaces 
  # The primary network interface
  auto eth0
  iface eth0 inet static
          address 212.XX.239.100
          netmask 255.255.255.240 
          network 212.XX.239.96
          broadcast 212.XX.239.111
          gateway 212.XX.239.97

  # ifconfig
  eth0      Link encap:Ethernet  HWaddr 52:54:00:d2:f7:31  
            inet addr:212.XX.239.100  Bcast:212.XX.239.111  Mask:255.255.255.240
            inet6 addr: fe80::5054:ff:fed2:f731/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:5631830 errors:0 dropped:0 overruns:0 frame:0
            TX packets:6683416 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:2027322829 (2.0 GB)  TX bytes:2076698690 (2.0 GB)

  
  A commandline which starts the KVM guest:
  /usr/bin/kvm -S -M pc-1.0 -enable-kvm -m 2048 -smp 1,sockets=1,cores=1,threads=1 -name mailer01 -uuid d41d1355-84e8-ae23-e84e-227bc0231b97 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/mailer01.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -drive file=/dev/mapper/vg_main-mailer01--root,if=none,id=drive-ide0-0-0,format=raw -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -drive file=/dev/mapper/vg_main-mailer01--swap,if=none,id=drive-ide0-0-1,format=raw -device ide-drive,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1 -netdev tap,fd=18,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:d2:f7:31,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -usb -vnc 127.0.0.1:0 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4

  Problem:
  ------------
  Periodically (at least once a day), one or more of the guests lose network connectivity.  Ping responds with 'host unreachable', even from the dom host. Logging in via the serial console shows no problems: eth0 is up, can ping the local host, but no outside connectivity.  Restart the network (/etc/init.d/networking restart) does nothing. Reboot the machine and it comes alive again.

  I've verified there's no arp games going on on the primary host (the
  arp tables remain the same before - when it had connectivity - and
  after - when it doesn't.

  This is a critical issue affecting production services on the latest
  LTS release of Ubuntu. It's similar to an issue which was 'resolved'
  in 10.04 but appears to have risen its ugly head again.

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