ubuntu 10.04; kvm bridged networking not working with public ip addresses

[senor_smile]

I have a dedicated hosted server box with ubuntu 10.04 64 bit installed. I would like to run kvm with ubuntu 8.04 installed for some php 5.2 compatible apps(they don't work right with php 5.3, the default in ubuntu 10.04).

I installed KVM as instructed at https://help.ubuntu.com/community/KVM/Installation . I installed the vm using virt-manager. I never could figure out how use virt-install or any of those automated installers. I just installed it using the disc. I set up bridged networking as per https://help.ubuntu.com/community/KVM/Networking . However, the bridged connection doesn't work.

Here's my /etc/network/interfaces on the host, running ubuntu 10.04. (with specific public ip blanked)

# 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

# The primary network interface
auto eth0
iface eth0 inet manual

auto br0
iface br0 inet static
        address xx.xx.xx.xx
        netmask 255.255.255.248
        gateway xx.xx.xx.xa
        bridge_ports eth0
        bridge_stp on
        bridge_fd 0
        bridge_maxwait 10

Here's my /etc/network/interfaces on the guest, running ubuntu 8.04.

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address xx.xx.xx.xy
netmask 255.255.255.248
gateway xx.xx.xx.xa

The two vm's can communicate to each other. But, the guest vm can't access anyone in the real world.

Here's my /etc/libvirt/qemu/store_804.xml

<domain type='kvm'>
  <name>store_804</name>
  <uuid>27acfb75-4f90-a34c-9a0b-70a6927ae84c</uuid>
  <memory>2097152</memory>
  <currentMemory>2097152</currentMemory>
  <vcpu>2</vcpu>
  <os>
    <type arch='x86_64' machine='pc-0.12'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/bin/kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/store_804.img'/>
      <target dev='hda' bus='ide'/>
    </disk>
    <disk type='block' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
    </disk>
    <interface type='bridge'>
      <mac address='52:54:00:26:0b:c6'/>
      <source bridge='br0'/>
      <model type='virtio'/>
    </interface>
    <console type='pty'>
      <target port='0'/>
    </console>
    <console type='pty'>
      <target port='0'/>
    </console>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes'/>
    <sound model='es1370'/>
    <video>
      <model type='cirrus' vram='9216' heads='1'/>
    </video>
  </devices>
</domain>

Any idea where I've gone wrong?

[binaryhat]

Did you get it to work?

[senor_smile]

Did you get it to work?

No, I didn't. It's still sitting there not working. I haven't found any information on how to fix it. Anyone have any ideas?

[binaryhat]

Try these steps: http://wiki.libvirt.org/page/Network...buntu_Bridging

Skip the part on Disabling NetworkManager.

I think the key step is :

Finally add the '/etc/sysctl.conf' settings
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
And then load the settings with
sysctl -p /etc/sysctl.conf

Thats what fixed it for me.

The docs provided by Ubuntu do not work, they are dated.

[binaryhat]

Any luck?

[shulegaa]

Without better bridged networking (config) documentation (with examples), KVM sure seems DOA for me. Bummer ...

I was just trying to consolidate physical servers into a bunch of VM's with static (bridged) IPs. It looks like more than a few folks are not getting very far with KVM.

[tomgibson]

I have managed to get a setup working on Ubuntu 10.04 with kvm guests and bridged networking albeit on a LAN with DHCP (not static public IPs), though I don't understand how as I certainly didn't follow all the instructions on the wiki.

Two things I notice about your config files that differ from mine:

1) In your /etc/network/interfaces you have an entry for eth0 and br0. I only have br0 in mine, now I'm not an expert in how this file works so you may have the eth0 entry for good reason, but as far as I know only the br0 entry is required.

2) In your vm .xml you specify the guest network interface using the lines

    <interface type='bridge'>
      <mac address='52:54:00:26:0b:c6'/>
      <source bridge='br0'/>
      <model type='virtio'/>
    </interface>

Try removing the <model /> line, I do not think this is necessary for bridged interfaces.

Not promising this will solve your problem, just a couple of things I noticed that differ from my own configs.

Only other thing I can suggest is perhaps your host firewall is interfering. The qemu faq has instructions on how to make this not happen:

http://qemu-buch.de/cgi-bin/moin.cgi...fe430c118b8b60

Hope that helps.

[TheR]

It looks more like a gateway problem.

You have a strange (very narrow) gateway mask. Is it the same as computers on the outside world?

Is gateway address same as gateway address of outside computers?

by
TheR