No keyboard, mouse, or monitor required at all. Not for beginners but not too hard.
Kickstart method
If you will be installing a Red Hat variant, you can use Kickstart. There are similar facilities for other distributions but I am not familiar with them. They will undoubtedly be very similar.
From web page referenced above:
Kickstart installations can be
performed using a local CD-ROM, a
local hard drive, or via NFS, FTP, or
HTTP.
To use kickstart, you must:
- Create a kickstart file.
- Create a boot diskette with the kickstart file or make the kickstart
file available on the network.
- Make the installation tree available.
- Start the kickstart installation.
There are a variety of ways in which you can meet the requirements above. Please refer to the the Kickstart page.
USB drive enclosure method
Place the drive in a USB enclosure and attach it to the laptop. Now there two things you can do.
- Use a virtual machine (you'd have to
install the software for this on the
laptop), assign the USB attached
drive to the VM, and install.
- Boot up the laptop with a Live CD and select the USB attached drive as the drive to install on.
For both of these methods you would only install enough software to get the box to boot, start the network service and then the SSH server. Thereafter, you would customize via SSH.
Your own customized LiveCD
Modify the LiveCD so that has an SSH server running and an SSH account to which you know the password. Boot up the headless box with it, SSH in and kick off the installation.
Just borrow a monitor and keyboard
How hard would that be? Temporarily deprive another computer. A mouse is not needed for text based installs. If you are a beginner this is your safest path. All of the others will be frustrating.
Regardless of the method used, any "headless" box needs some way of communicating its status to the outside world other than by just sitting there emitting heat. If you haven't really tightened down the OS, the drivers, the configuration, in short, everything (enough to make you an embedded device guru) then you must at least get a used, cheap LCD and a cheap keyboard and attach them to the "headless" box for trouble shooting. Even datacenters have crash carts that have these things just in case.