[Bug 997978] Re: KVM images lose connectivity with bridged network
Serge Hallyn
997978 at bugs.launchpad.net
Thu Jun 14 22:55:35 UTC 2012
Quoting Georg Leciejewski (vespaschorsch at gmx.de):
> @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
One thing I notice here is that you have an ip address on eth0, which I
assume is bridged with br0?
When I bridge eth0 to br0 using the following /etc/network/interfaces:
=========================
auto lo
iface lo inet loopback
auto br0
iface br0 inet dhcp
bridge_ports eth0
# The primary network interface
auto eth0
iface eth0 inet manual
=========================
I get the following ifconfig -a output:
=========================
br0 Link encap:Ethernet HWaddr fa:16:3e:59:27:16
inet addr:10.55.60.89 Bcast:10.55.60.255 Mask:255.255.255.0
inet6 addr: fe80::f816:3eff:fe59:2716/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:223 errors:0 dropped:0 overruns:0 frame:0
TX packets:178 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:21627 (21.6 KB) TX bytes:19555 (19.5 KB)
eth0 Link encap:Ethernet HWaddr fa:16:3e:59:27:16
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:259 errors:0 dropped:0 overruns:0 frame:0
TX packets:178 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:26871 (26.8 KB) TX bytes:19487 (19.4 KB)
=========================
What does your /etc/network/interfaces look like?
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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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