[Libvir] QEMU without KVM

Daniel P. Berrange berrange at redhat.com
Thu May 17 16:54:16 UTC 2007

On Thu, May 17, 2007 at 09:39:01AM -0400, Steven W. Moyer wrote:
> Thanks Dan!   I was indeed missing some modules (I just switched to the 2.6.20 kernel series and didn't find a couple of the necessary switches in menuconfig).  I'm still having problems with the networking.
> If I try to start libvirt_qemud without have the bridge defined, I get this error:
> smoyernew images # libvirt_qemud --system
> iptables: Invalid argument
> Failed to autostart network 'default': failed to add iptables rule to allow forwarding to 'virbr0' : Invalid argument

This indicates that iptables failed to add the stateful forwarding
rules, eg this rule

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 ACCEPT     all  --  *      virbr0      state RELATED,ESTABLISHED 

This says you're still missing some iptables kernel moodules.


Are the relevant ones i believe.

> If I create virbr0 and then start libvirt_qemud, I get this error:
> smoyernew images # libvirt_qemud --system
> Failed to autostart network 'default': cannot create bridge 'virbr0' : File exists

Yep, manually creating virbr0 is a really bad idea & will ultimately
not work, because you still need the iptables rules which were failing

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