Multiple system configs on same Ubuntu install

[Rashkae]

Thiers Botelho wrote:
> Hi all,
> 
> Short question #1:
> If I want to have an Ubuntu instance with no X-server, AND another instance
> with an X-server + LXDE, is it possible to achieve this with a SINGLE
> install instead of a dual-boot ? I'd be using either one OR the other setup
> at a time.
> 
> Long question:
> I'm more or less of a noob regarding Linux and a total noob as to Ubuntu.
> I'm planning to build an Ubuntu box just for hosting VirtualBox VMs, and
> just learned that I can use a Linux instance without an x-server to achieve
> that with VBoxHeadless (while hopefully learning quite a lot in the
> process).
> OTOH, I'd welcome being able to use the full VBox Gui to ease my learning
> curve while setting up and tweaking the host and its VMs, and be able to
> reboot at will when done with tweaking under the GUI and switching to a
> X-less environment just to run VMs.
> So my initial thought was of a dual-boot setup - one Ubuntu instance with an
> X-server + LXDE, and another instance with no X-server - but then it
> occurred to me that Ubuntu might allow me to achieve the same results with a
> SINGLE install, where I might use GRUB entries, or maybe init scripts, or
> maybe another toolset to toggle at will between both system layouts.
> Is this at all possible ?
> 
> Short question #2:
> If the answer to #1 could be YES, what would be the best tools to perform
> this ?

X and the gnome desktop are just programs that are installed and run,
not some kind of magic different Ubuntu version.  If you want them
available, they have to be installed.  If you don't want them to start
up automatically, you can turn off GDM from the start up sequence, (it
should be in the System -> Administration -> Services GUI.)

Then you would have to log in and type the 'startx' command to start the
GUI Desktop.

You can make customizations that will allow you to choose how the system
starts up from the Grub Menu, but those customizations are significantly
more complex now that Ubuntu uses upstart instead of the old sysinit,
and I would suggest they are probably too steep an effort for your
relatively simply needs.

For that matter, there is little advantage in disabling the GUI log in
manager, the memory footprint you would save is small.