[Lxc-users] veth interface not deleted?

[Fajar A. Nugraha]

On Thu, Sep 12, 2013 at 9:46 PM, Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> Quoting Fajar A. Nugraha (list at fajar.net):
>> Any ideas how to troubleshoot this? Is this something related to kernel
>> version?
>
> If the container fails to start at all, then lxc will manually delete
> the veth.

The case is the container is already running, and then you stop it.
Depending on the traffic handled by the container, the veth will
sometimes not get deleted.

This becomes a problem later on becase I'm using persistent MAC,
interface name (lxc.network.veth.pair), and IP address (on the
container side), so when I start the container later (e.g. lxc-start,
or when using "init 6" within the container) it fails to start (due to
conflicting interface name, and even if I don't use persistent name it
probably won't be able to function properly later due to conflicting
IP address)

>  However if we get as far as lxc passing one end of the
> veth tunnel into the container, then when the container dies the
> veth should be deleted by the kernel.

The key word there is "should" :)

>
> Have you been using lxc-attach?

Nope. lxc-start, lxc-stop, lxc-console, and commands inside the
containers (e.g. shutdown, init 6)

> I wonder if something is pinning the
> network namespace so that it isn't deleted.  In that case the veth
> wouldn't get autoreaped.


Again, whether this happens or not seems to depend on the network
traffic. I can reliably reproduce it on our production container
(obviously I can't do it often or too long), but I'm having problems
reproducing it on test lab (i.e. how do you reproduce 2000 concurrent
connections from different clients with  5 Mbps traffic on a test
lab?).

I'm open to ideas and suggestions.

-- 
Fajar