[lxc-users] unable to start qemu-kvm inside lxc container (the host freezes)

[Fajar A. Nugraha]

On Thu, Apr 16, 2015 at 8:57 PM, Syraxes <syraxes at gmail.com> wrote:
> On Thu, Apr 16, 2015 at 11:50 AM, Fajar A. Nugraha <list at fajar.net> wrote:
>>
>>
>> Have you tested using kvm WITHOUT network for the VMs, by any chance?
>>
>> I tested something similar with virtualbox inside a container, and
>> virtualbox's networkless-vm start fine. However it crash immediately
>> when I use bridge network for the VMs.
>>
>> Hopefully this can help you pinpoint the source of the problem.
>
>
> This suggestion is interesting.  The problem seems to be related to
> the networking of the vm :
> - the qemu vm started (no freeze)  when i removed all the network
> interfaces ( 6 tap devices )
> - when I try to create a bridge  _inside_ the container ,  the system
> froze  . This happened without even trying to start the qemu ...
>
> I'll keep investigating ...
>
>
> In principle :  is it possible to create network bridges inside lxc
> containers  , which are not seen by other containers ?  What about tap
> devices?
> (  I'll need that each container has its own set of 36 tap devices and
> 6 bridges - isolated from other containers )


Bridges definitely works, nested containers uses that functionality.
If it crashed it your setup, try with a more up-to-date kernel and lxc
(e.g. ubuntu utopic with ubuntu-lxc/daily ppa)

virtualbox with host-only network works, kindof. I had to passtrhu
vboxnet* interface from the host to the container using
"lxc.network.type = phys".

bridging - using virtualbox's bridging - crash whether its to the
container's eth0 (veth), a brigde, or a dummy interface.

bridging veth (as used by nested containers) works, as well as
bridging a dummy interface.

So it looks like virtualbox bridge problem in my case (still doesn't
work with vivid's 3.19 kernel and lxc daily). You might have better
luck with qemu if you update kernel/lxc.

-- 
Fajar