[lxc-devel] veth interface not deleted after container shutdown

[Daniel Lezcano]

Denis Rizaev wrote:
> Hello, i'm running lxc in production for 1 month and noticed bug that
> high-loaded veth interfaces are not destroyed after lxc-stop.
> This results in errors when we try to start this container again. As
> workaround i manually do something like ip link del veth_<container_name>.
> I have two high-traffic containers(~10 mbit/s each) and this bug appears on
> them. Other six almost idle containers destroying it's veth's interfaces
> properly.
>   
The veth interfaces, as any virtual interfaces in the network namespace 
are automatically destroyed by the kernel when a network namespace is 
destroyed.

The network namespace is destroyed when there is no more ref count on 
it. And the processes, the sockets, the routes and some more things get 
a refcount on it when they are created.

So, you may check if after a long time (at least all tcp timers have 
expired, so the sockets are destroyed), the interfaces are still there. 
If this is the case, then the kernel does not release on refcount 
somewhere and it's probably a kernel bug.