[Lxc-users] lxc-execute-ephemeral?

[Dan Kegel]

On Thu, Aug 23, 2012 at 11:25 AM, Serge Hallyn
<serge.hallyn at canonical.com> wrote:
> Is your main objection the extra time it takes for the distro-provided
> init to run over lxc-init, or using separate commands as you mention
> above?

I'm still trying to figure out my requirements, and how to use lxc.
Buildbot runs normally take at least a minute, so anything
under ten seconds might be ok.  My main concern was
how to issue commands to run inside the ephemeral container.
I can make do with running a single command, but buildbot
kind of wants to run several commands during a run, so
starting, issuing multiple commands from outside the container,
and then stopping would be a natural fit.

> lxc-start-ephemeral takes arguments to execute, so you can
> just do
>
>   lxc-start-ephemeral -o q1 -- ps -ef
>
> which will create the container, run the command, and destroy the container,

Sounds good, but when I try it, I get prompted for root's password:

$ time sudo lxc-create -t ubuntu -n test-container2
...
real	0m5.970s   (nice!)
$ sudo lxc-start-ephemeral -o test-container2 -- ps -ef
Setting up ephemeral container...
unable to write 'random state'
Starting up the container...
Warning: Permanently added '10.0.3.175' (ECDSA) to the list of known hosts.
root at 10.0.3.175's password:
Permission denied, please try again.
root at 10.0.3.175's password:

I had to reboot (lxc-stop wasn't enough?) and do lxc-destroy to get
rid of the ephemeral container.

So I'm not sure it's working quite as you indicated.  This is all on
ubuntu-12.04,
$ dpkg-query -W lxc
lxc	0.7.5-3ubuntu62

If you have a clue you could lend me, I'd be grateful.

> If you want to use lxc-init, it an lxc-execute-ephemeral shouldn't be too
> hard to whip up.

Hopefully I can make do with what's already there, once I figure out
how to use it.
- Dan