[Lxc-users] Ubuntu 12.04 linux-container package and init modifications

[Stéphane Graber]

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On 03/06/2012 11:03 PM, Fajar A. Nugraha wrote:
> On Wed, Mar 7, 2012 at 10:45 AM, Serge Hallyn 
> <serge.hallyn at canonical.com> wrote:
>> Quoting Fajar A. Nugraha (list at fajar.net):
>>> # cat /etc/init/lxc-lo.conf start on startup env container
>>> 
>>> pre-start script if [ "x$container" != "xlxc" -a "x$container" 
>>> != "xlibvirt" ]; then stop; fi initctl start network-interface 
>>> INTERFACE=lo exit 0; end script
>>> 
>>> 
>>> So now the modifications (both from lxcguest and my local 
>>> addition) are all new .conf files, which would be ignored if 
>>> it's not started in lxc environment. Might try 12.04 container 
>>> later.
>> 
>> If your guest is uptodate 12.04, you should have
>> 
>> /etc/init/network-interface-container.conf
>> 
>> from ifupdownpackage which emits that signal for you.  You 
>> shouldn't need your own lxc-lo.conf any more.
> 
> What is Canonical's plan for older guests? Will 
> network-interface-container.conf be backported to lxc-guest, or 
> will manual configuration still necessary?

Starting in 12.04 we did the necessary changes to upstart, udev,
mountall, ifupdown, ... to be container aware. For older releases our
template still installs lxcguest that does a similar job though a bit
more hackish :)

As Serge said, if anything doesn't start for you with a clean 12.04
container running on 12.04, it's a bug and we want to fix it.

My goal for 12.04 was to make a perfectly clean and standard Ubuntu
system work in a container without any change whatsoever and I think
we achieved this:
http://www.stgraber.org/2012/03/04/booting-an-ubuntu-12-04-virtual-machine-in-an-lxc-container/


If you're writing custom upstart jobs or other scripts, you may be
interested by the new events and tools we introduced on all Ubuntu
systems since 12.04:
 - The upstart "container" event giving you CONTAINER=technology
 - The upstart "not-container" event
 - /bin/running-in-container that will exit 0 in a container and exit
1 otherwise, even it exits 0 it'll also print the technology.

I added code to upstart to detect (referred above as "technology"):
 - lxc
 - lxc-libvirt
 - openvz
 - vserver

Though we only really support lxc and lxc-libvirt, the rest is best
effort and we expect people to give us patches or access to a machine.

This means the upstart job below is now possible:
start on container CONTAINER=lxc
exec /usr/sbin/my-lxc-monitoring-service


I hope this helped explain what we're doing in 12.04.
I'm planning on a generic "what's new in LXC for 12.04" blog post in
the next few days, once we've turned apparmor back on and have
somewhat secure containers again (hopefully later today).

Again, please try an up to date Ubuntu 12.04 system and report any bug
that you see, we're trying to closely look at LXC bugs and fix them as
soon as possible.

Cheers

- -- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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