[Bug 616064] Re: Broken networking in kvm guests

Tue Dec 20 15:58:35 UTC 2011

Well I've tried this (after first steps with git)

# terminal 1
root at vs-master:~# ip link add type veth

# terminal 2
root at vs-master:~# /bin/ns_exec -cmn /bin/bash 
about to clone with 40020000
clone: Invalid argument
root at vs-master:~# echo $$
7934

# terminal 1
root at vs-master:~# ifconfig veth0 0.0.0.0 up
root at vs-master:~# brctl addif virbr0 veth0
bridge virbr0 does not exist!
root at vs-master:~# brctl addif virbr1 veth0
root at vs-master:~# ip link set veth1 netns 7934

# terminal 2
root at vs-master:~# ifconfig veth1 up
root at vs-master:~# dhclient veth1
There is already a pid file /var/run/dhclient.pid with pid 15307
killed old client process, removed PID file
Internet Systems Consortium DHCP Client V3.1.3
Copyright 2004-2009 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/veth1/1a:13:2e:39:53:2e
Sending on   LPF/veth1/1a:13:2e:39:53:2e
Sending on   Socket/fallback
DHCPDISCOVER on veth1 to 255.255.255.255 port 67 interval 7
DHCPOFFER of 192.168.122.61 from 192.168.122.1
DHCPREQUEST of 192.168.122.61 on veth1 to 255.255.255.255 port 67
DHCPACK of 192.168.122.61 from 192.168.122.1
SIOCADDRT: No such process
bound to 192.168.122.61 -- renewal in 1771 seconds.

# terminal 1
root at vs-master:~# nc -4 -k -l 9999

# terminal 2
root at vs-master:~# while [ 1 ]; do
> echo ab | nc 192.168.1.200 9999
> sleep 0.5s
> done

All had gone well, I had "ab" lines in terminal 1 without interruption.
I've enhanced the terminal 2 script in order to check if "ab" was still comming into terminal 1 (because I've been a little lost with a big pile of ab) :
# N=1; while [ 1 ]; do echo ab$N | nc 192.168.1.200 9999; ((N += 1)); sleep 0.5s; done
No problem.
I switched to "sleep 0.01s" and still no problem.
Last script to test content length :
# S=a; N=1; while [ 1 ]; do echo $N$S | nc 192.168.1.200 9999; ((N += 1)); S=${S}a; sleep 0.01s; done
No problem.

But actually, my VM is using br0 (with static IPs in 192.168.1.0
network) rather than virbr1 so how could I test this ?

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https://bugs.launchpad.net/bugs/616064

Title:
  Broken networking in kvm guests

Status in “bridge-utils” package in Ubuntu:
  Confirmed
Status in “linux” package in Ubuntu:
  Confirmed
Status in “qemu-kvm” package in Ubuntu:
  Confirmed

Bug description:
  Binary package hint: qemu-kvm

  Some TCP operations receive unexpected reset (RST) packets when executed on the guest.  I can see these RST packets via
  Wireshark but can't explain their source.  This breaks certain (most) networking on the guest.

  I uncovered this when some 'git clone' operations failed with "Broken
  Pipe" in the guests.  I've been able to reproduce the same failures
  using scp and 'svn checkout'.  The failure occurs 80-90% of the time
  and 'svn checkout' seems to be the quickest to fail.  The same
  operations on the host are always successful.

  My setup is a Lucid amd64 host with two guests (Lucid and Hardy, both
  i386, using kvm).  Networking seems to mostly work.  I can maintain
  persistent ssh connections to the guest and some networking operations
  from the guest (ie. ping) never fail.  However, the git-clone/scp/svn-
  checkout operations fail almost all the time.  I've tried this with
  both virtio and e1000 drivers with no difference.

  This may be similar to some of the behavior reported in bug 584048 but
  not the final patch referenced in comment 27.  I built a custon deb
  including the upstream patch for testing and it had no effect.

  $ lsb_release -rd
  Description:	Ubuntu 10.04.1 LTS
  Release:	10.04

  $ apt-cache policy qemu-kvm
  qemu-kvm:
    Installed: 0.12.3+noroms-0ubuntu9.2
    Candidate: 0.12.3+noroms-0ubuntu9.2
    Version table:
   *** 0.12.3+noroms-0ubuntu9.2 0
          500 http://us.archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
          100 /var/lib/dpkg/status
       0.12.3+noroms-0ubuntu9 0
          500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages

  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: kvm 1:84+dfsg-0ubuntu16+0.12.3+noroms+0ubuntu9.2
  ProcVersionSignature: Ubuntu 2.6.32-24.39-server 2.6.32.15+drm33.5
  Uname: Linux 2.6.32-24-server x86_64
  Architecture: amd64
  Date: Tue Aug 10 16:39:24 2010
  InstallationMedia: Ubuntu-Server 10.04 "Lucid Lynx" - Beta amd64 (20100406.1)
  KvmCmdLine:
   UID        PID  PPID  C    SZ   RSS PSR STIME TTY          TIME CMD
   root     17641     1  1 2174883 1087144 1 15:42 ?      00:00:59 /usr/bin/kvm -S -M pc-0.12 -cpu qemu32 -enable-kvm -m 8192 -smp 8 -name hound-lucid -uuid 0e32438c-cb4d-1eb9-a560-f25c89c1dbf6 -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/hound-lucid.monitor,server,nowait -monitor chardev:monitor -boot c -drive file=/opt/hound-lucid,if=virtio,index=0,boot=on -drive if=ide,media=cdrom,index=2 -net nic,macaddr=52:54:00:61:7e:c0,vlan=0,model=virtio,name=virtio.0 -net tap,fd=59,vlan=0,name=tap.0 -chardev pty,id=serial0 -serial chardev:serial0 -parallel none -usb -vnc 127.0.0.1:0 -k en-us -vga cirrus
  MachineType: IBM IBM System x3400 M2 Server -[7836AC1]-
  ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-24-server root=UUID=7d9adc6b-cfec-42fa-b469-bc09ccd24478 ro quiet
  ProcEnviron:
   PATH=(custom, user)
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: qemu-kvm
  dmi.bios.date: 11/20/2009
  dmi.bios.vendor: IBM Corp.
  dmi.bios.version: -[Y4E131BUS-1.02]-
  dmi.board.name: 49Y6715
  dmi.board.vendor: IBM
  dmi.board.version: GA
  dmi.chassis.type: 23
  dmi.chassis.vendor: IBM
  dmi.chassis.version: GA
  dmi.modalias: dmi:bvnIBMCorp.:bvr-[Y4E131BUS-1.02]-:bd11/20/2009:svnIBM:pnIBMSystemx3400M2Server-[7836AC1]-:pvr06:rvnIBM:rn49Y6715:rvrGA:cvnIBM:ct23:cvrGA:
  dmi.product.name: IBM System x3400 M2 Server -[7836AC1]-
  dmi.product.version: 06
  dmi.sys.vendor: IBM

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