[libvirt] PATCH: 0/7: Re-factor LXC driver

[Daniel P. Berrange]

On Tue, Aug 05, 2008 at 02:17:27PM -0700, Dan Smith wrote:
> DB> This is a long overdue followup to my previous set of patches to
> DB> make the LXC driver use the new domain XML apis.
> 
> Have you been able to test this with NET_NS support enabled yet?
> 
> I am hitting the same issue I was before.  On starting an LXC domain
> with a network interface, the daemon finishes the action and reports
> a good status to virsh.  The domain fails to start, with the following
> in the per-domain log file:
> 
>   DEBUG: lxc_container.c: lxcContainerStart (clone() returned, 8082)
>   libvir: Linux Container error : internal error read of fd 6 failed: Input/output error 
>   DEBUG: veth.c: vethDelete (veth: veth2)
> 
> However, now, the daemon crashes well after leaving the LXC driver's
> domain startup process.  From the timing, I'd guess it's in some event
> (or SIGCHLD) handler, but I can't reproduce it in gdb to get more
> information.

That's not good. There should be no SIGCHLD's anywhere now - the container
double-forks into the background. Its probably some error in the cleanup
path - valgrind may help if gdb fails.

> This looks to be identical in root cause to what I was seeing with the
> previous set of patches, and was unable to figure out why file
> descriptor 6 was getting prematurely closed.  I'll get started on
> debugging it again tomorrow, but it might be good if you can reproduce
> it as well :)

I've unfortunately still not got a  kernel build with all the neccessary
NET_NS bits added on. If you can capture an strace it can probably 
help me diagnose the problem

   strace -f -ff -o net.log -s 30000 -p `pid of libvirtd`

IIRC, you said removing the bit of code which closed all open file descriptor
would make it work again ?  If you can grab an strace with that change in 
too I can compare and figure out where we're going wrong.


Daniel
-- 
|: Red Hat, Engineering, London   -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505  -o-  F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|