[libvirt-users] lxc arp doesn't work at start for several seconds

[Laine Stump]

On 07/26/2014 09:09 PM, Jonathan Rudenberg wrote:
> On Jul 26, 2014, at 2:05 PM, Jonathan Rudenberg <jonathan at titanous.com> wrote:
>
>> I’m running into an issue with libvirt-lxc networking. I have an init program that configures the eth0 interface with an IP and gateway when the container starts. I noticed that programs running in the container encountered “no route to host” errors and looked into it further. What I found is that ARP packets are not making it onto the gateway during the first few seconds of the container’s life.
> I found the issue: STP was enabled on the virbr0 which spends 2s in each of the Listening and Learning states by default before enabling the interface.
>
> A simple `brctl stp virbr0 off` solves this issue.

To avoid needing to manually set it in the future, you can set it in
libvirt's default network configuration. Just edit it:

   virsh net-edit default

and change the <bridge> line to this:

  <bridge name='virbr0' stp='off'/>

I'm surprised that leaving stp='on' with delay='0' would still create
this behavior - can you verify that is current setting for your default
network (use "virsh net-dumpxml default" to see the current setting)