I wanted to setup an Ubuntu 7.10 (Gutsy) server to be a sandbox on my Vista notebook using VirtualBox. Seems there is a known problem with running the Ubuntu server kernel (defaults to PAE and the kernel reports 'CPU Too Old' on boot and bails, seem VirtualBox does not yet support PAE extensions) via VirtualBox, however this can be made to work by switching out to the generic kernel and using that. Sure it's not ideal for a production level server, but it works great in a sandbox mode.

Step-by-step 1, 2, 3 sort-of directions:

• Download the Ubuntu 7.10 Server ISO (BitTorrent FTW!)
• Download and install VirtualBox
• Setup a new VM instance
  • Recommended settings: OS Type of Linux 2.6,  512MB RAM, 20GB Dynamic Drive, 8MB Video, USB + EHCI, Network NAT (see my post about port forwarding if you need to interact with this VM via your LAN machines).
• Set the new VM instance CD/DVD-ROM to mount the ISO
• Install with basically all defaults, let the CD eject and then the OS will reboot the VM
• Boot again from your ISO mounted CD to get the initial install screen
• This time select the 'Rescue a broken system' option from the menu
• Go back though like you are setting the system backup (keyboard, locale, hostname, etc.) this is just used to boot up the installer
• At the Rescue Mode screen be sure and choose your root (/) partition, in my case it was /dev/sda1
• At the '[!!] Enter rescue mode' screen pick the 'Execute a shell in /dev/sda1' option
• From here you will be in a shell from your chrooted installed server, execute these commands (press 'Y' to install any needed additional packages  and press 'Y' to confirm):
  • apt-get update
  • apt-get install linux-image-generic
  • apt-get remove linux-server
• Now you need to change Grub to use the linux-generic as the default item to boot from. This is done by setting the 'default x' value to be the number of the 'title' block in the menu.lst file. This should be the third block (two linux-server entries and then two more linux-generic entries):
  • nano -w /boot/grub/menu.lst
  • <find the 'default 0' and change to be the number of your linux-genric entry, should be 2 (remember computers count from 0, duh!)>
  • <with Nano its CTRL+X to save the file press 'Y' to confirm the overwrite>
  • exit
• The 'exit' command should exit you out of the shell and then reboot the VM instance.
• I would recommend doing both a Snapshot from within VirtualBox (this gives you a reference point in time position you can 'clean' your sandbox back to. Do this before you start monkeying around with your server, else you will have to start again to get it back in a pristine condition.
• Enjoy!