installing on running system

[Skaperen]

i'd like to do an install targeting a spare drive attached to a running system while keeping that system up. doing it via a VM seems the obvious way (BTDT). any tools exist to do it more direct?

[ubfan1]

Take a look at http://askubuntu.com/questions/201521/installing-ubuntu-to-other-disk-from-running-system
There are several answers.

[Skaperen]

i am wanting a "real system" install (that i can do "apt-get update && apt-get -y upgrade" on) ... the VM install does that. and i want a fresh system, not a copy of the one that is running. i was hoping the installer code could be run with a target argument.