Replace sysvinit to upstart.

I happend to find /sbin/init in my debian box doesn't derive from upstart package. It seemed sysvinit still remain in installation of debian sid.
I chose to install upstart, I did as following procedures,

Step 1. sudo aptitude remove sysvinit.
(It may ask to type 'I am aware that this is a very bad idea' phrase to remove sysvinit.)

Step 2. sudo aptitude install upstart.
Step 3. reboot.

After reboot,/sbin/init of upstart is invoked.