[lxc-devel] How does the console work in most recent release?

[Daniel Lezcano]

On 01/04/2011 09:36 AM, Rob Landley wrote:
> I'm attempting to write a simple HOWTO for setting up a container with 
> LXC.  Unfortunately, console handling is really really brittle and the 
> only way I've gotten it to work is kind of unpleasant to document.
>
> Using lxc 0.7.3 (both in debian sid and built from source myself), I 
> can lxc-create a container, and when I run lxc-start it launches init 
> in the container.  But the console is screwy.
>
> If my init program is just a command shell, the first key I type will 
> crash lxc-start with an I/O error.  (Wrapping said shell with a script 
> to redirect stdin/stdout/stderr to various /dev character devices 
> doesn't seem to improve matters.)
>
> Using the busybox template and the busybox-i686 binary off of 
> busybox.net, it runs init and connects to the various tty devices, and 
> this somehow prevents lxc-start from crashing.  But if I "press enter 
> to active this console" like it says, the resulting shell prompt is 
> completely unusable.  If I'm running from an actual TTY device, then 
> some of the keys I type go to the container and some don't.  If my 
> console is connected to a PTY when I run lxc-start (such as if I ssh 
> in and run lxc-start from the ssh session), _none_ of the characters I 
> type go to the shell prompt.
>
> To get a usable shell prompt in the container, what I have to do is 
> lxc-start in one window, ssh into the server to get a fresh terminal, 
> and then run lxc-console in that second terminal.  That's the only 
> magic sequence I've found so far that works.
>
> The attached html file is a long drawn-out reproduction sequence for 
> this.
>
> I tried downloading lxc-git to see if this is already fixed, but 
> running "autoconf" doesn't seem to want to produce a ./configure file 
> for me. ("configure.ac:8: error: possibly undefined macro: 
> AM_CONFIG_HEADER") I'm really not an autoconf expert (the whole thing 
> is just a horrible idea at the design level), so have no idea what I'm 
> doing wrong there.

Hi Rob,

there is a small bug when installing the template in the inittab, it 
should be:

::sysinit:/etc/init.d/rcS
tty1::respawn:/bin/getty -L tty1 115200 vt100
console::askfirst:/bin/sh

Otherwise, I think the busybox version you are using is bogus. I had the 
same problem than you but I installed busybox-1.18.1, compiled as 
static, ran the template script, modified the inittab and it works like 
a charm.

Thanks for reporting the problem

   -- Daniel