plymouth isn't working in lxc containers

[Stéphane Graber]

root@upstart-test:~# tty
/dev/lxc/console
root@upstart-test:~# start plymouth
plymouth start/running, process 436
root@upstart-test:~# start plymouth-splash
<4>init: console-font main process (439) terminated with status 1
<4>init: setvtrgb main process (442) terminated with status 1
plymouth-splash start/running, process 441
root@upstart-test:~# plymouth ask-for-password --prompt 'open sesame: '
root@upstart-test:~# ps faux | grep plymouth
root 445 0.0 0.0 6532 632 lxc/console S+ 00:01 0:00 \_ grep --color=auto plymouth
root 436 0.0 0.0 34792 1236 ? S 00:00 0:00 @sbin/plymouthd --mode=boot --attach-to-session
root@upstart-test:~# stop plymouth
plymouth stop/waiting

[Stéphane Graber (stgraber)]

The log above is from a simple raring 64bit lxc container (lxc-create -n p1 -t ubuntu -- --release raring --arch amd64) started with lxc-start (lxc-start -n p1) with the current tty attached to the /dev/console equivalent in lxc.

[Steve Langasek (vorlon)]

Looks like this is caused by the lack of any plymouth themes in the default lxc environment. Installing the plymouth-theme-ubuntu-text package, the following works:

# service tty2 stop
tty2 stop/waiting
# plymouthd --mode=boot --attach-to-session --tty=/dev/tty2
# plymouth show-splash
#

connecting to tty2 with 'lxc-console -n p1 -t 2' shows me the expected text splash screen.

# plymouth ask-for-password --prompt 'open sesame: '
#

the prompt is shown.

So either lxc should mask the 'splash' argument in /proc/cmdline by default, or plymouth-theme-ubuntu-text should be included.

The other problem is that by default, plymouth in Ubuntu looks to /dev/tty7, which isn't mapped anywhere usable under lxc. This could also be forced by forcing an alternate kernel commandline, such as 'console=/dev/lxc/console'.

If /proc/cmdline itself isn't virtualized, I'd be ok with a patch to /etc/init/plymouth.conf to pass an appropriate --kernel-command-line argument when in a container, provided it can be done in the same way as /etc/init/container-detect.conf using env vars. (AIUI, there may be a LIBVIRT_LXC_CMDLINE variable for this?)