4th network extremely slow/broken

[Jamin W. Collins]

Binary package hint: kvm

Lenovo Thinkpad T61p
Intel(R) Core(TM)2 Duo CPU T8300 @ 2.40GHz
2.5G RAM
Ubuntu Hardy w/ all updates

Guest machines were created using virt-manager (0.5.3-0ubuntu10). Four networks defined 2x public (NAT to any physical interface), 2x private. Three guests created running fully updated Ubuntu Hardy. On all guests the order of the networks assigned to the virtual NICs was the same. First the two public networks on eth0 and eth1, followed by the private networks on eth2 and eth3. On each machine the first three interfaces (eth0, eth1, and eth2) worked flawlessly with ping responses between virtual machines of sub 2ms. However, on each machine pings to the private network connected to eth3 failed, unless targeted to the local machines IP address. Adding virtio to the network definition improved things somewhat as responses were now received. However, the response time for this network was extraordinarily high with an average of 1000+ms.

I've tested various combinations of the networks present. In all cases, if the number of networks is reduced to three or less everything works fine.

Please let me know if I can provide any further information.

[Dustin Kirkland  (kirkland)]

Hi James-

I'd like to try to reproduce this issue.

Can you give me a bit more detail about your network configuration, such as /etc/network/interfaces? How were your private networks created?

Also, could you please paste the command line used to launch the virtual machine?

Thanks,
:-Dustin

[Jamin W. Collins (jcollins)]

It's Jamin...

All virtual machines and network interfaces were/are created via virt-manager and libvirt. The host system's network interface is managed by Network Manager and is normally the wireless interface, though I do recall testing both wired and wireless for the host.

$ cat /etc/libvirt/qemu/networks/default.xml
<network>
  <name>default</name>
  <uuid>5add1e4c-ef0c-4916-90ea-9e8a3e094a06</uuid>
  <bridge name="virbr%d" />
  <forward/>
  <ip address="192.168.122.1" netmask="255.255.255.0">
    <dhcp>
      <range start="192.168.122.2" end="192.168.122.254" />
    </dhcp>
  </ip>
</network>

$ cat /etc/libvirt/qemu/networks/public_1.xml
<network>
  <name>public_1</name>
  <uuid>14447e17-0cad-e139-e9b5-4eb9315e99b0</uuid>
  <forward/>
  <bridge stp='on' forwardDelay='0' />
  <ip address='192.168.51.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.51.128' end='192.168.51.254' />
    </dhcp>
  </ip>
</network>

$ cat /etc/libvirt/qemu/networks/private_1.xml
<network>
  <name>private_1</name>
  <uuid>c7db1f0e-32fa-5aa6-7940-5007abd669e7</uuid>
  <bridge stp='on' forwardDelay='0' />
  <ip address='192.168.61.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.61.128' end='192.168.61.254' />
    </dhcp>
  </ip>
</network>

$ cat /etc/libvirt/qemu/networks/private_2.xml
<network>
  <name>private_2</name>
  <uuid>edbe0a6b-fe46-1f23-66fa-bacd2ff7e5e6</uuid>
  <bridge stp='on' forwardDelay='0' />
  <ip address='192.168.62.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.62.128' end='192.168.62.254' />
    </dhcp>
  </ip>
</network>

$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

[Jamin W. Collins (jcollins)]

As for command line used to launch the VM, they are all started from within virt-manager, not from the command line.

[Jamin W. Collins (jcollins)]

This is has a status of Incomplete for kvm, what additional information or assistance can I provide for this?

[Dustin Kirkland  (kirkland)]

Jamin-

When you can reproduce this problem, would you please grab the output of `ps -ef | grep kvm` and paste that here?

The status for kvm is incomplete because I can't see how to reproduce this using kvm alone (without virt-manager). If this problem is only around when running through virt-manager, then the bug would have to be somewhere in libvirt or virt-manager, rather than kvm.

:-Dustin

[Marc Deslauriers (mdeslaur)]

Are you still able to reproduce this issue with a current version of Ubuntu, such as Ubuntu 10.10 (Maverick)?

[Launchpad Janitor (janitor)]

[Expired for virt-manager (Ubuntu) because there has been no activity for 60 days.]