I need ubuntu 12.04 with developing web-services running (sshd, apache2.2, php5.3, mysql-server). I have ubuntu 14.04, i installed docker.
Then i started container:
There is no init process running inside the container. Therefore the runelevel can't be determined. If there is an unknown runlevel, upstart can not start mysql. ... see /etc/init/mysql.conf
...
start on runlevel [2345]
...
If you try to check the runlevel:
$ runlevel
unknown
... you see it is unknown.
In Docker it is the common way to start the application in foreground.
/usr/bin/mysqld_safe
If you want to start more than one application, you can use supervisord.
http://supervisord.org/
https://docs.docker.com/articles/using_supervisord/
Additional i've found a Dockerfile, which starts a init inside a ubuntu:12.04 docker container. Really nice work:
https://github.com/tianon/dockerfiles/blob/master/sbin-init/ubuntu/upstart/12.04/Dockerfile