Before an operating system can be installed, an ISO image must be downloaded from the Internet and attached to the virtual machine as a CD. The Ubuntu 14.04 LTS Server operating system can be downloaded from the following location:
http://www.ubuntu.com/download/server
Once the ISO is downloaded, perform the following steps:
Select the virtual machine in VirtualBox Manager and click on the Settings icon. Click on the Storage icon to manage the storage options:
Figure B.20
Click on the first CD icon labeled Empty to modify the Primary IDE Slave controller. Click on the CD icon to attach the ISO to the virtual machine. When prompted, click on Choose Virtual Optical Disk File to find the ISO on the local machine:
Figure B.21
Select the ISO and click on Open to attach the image. Once attached, the image will be listed under the IDE controller:
Figure B.22
Click on OK to close the settings window.
From VirtualBox Manager, select the virtual machine and click on the Start icon:
Figure B.23
The virtual machine will boot off the CD image and present you with the installation screen:
Figure B.24
Installing the guest operating system is outside the scope of this book. However, there are plenty of guides available on the Internet, including the following from Ubuntu:
https://help.ubuntu.com/lts/serverguide/installing-from-cd.html
It is safe to ignore the prompts to configure networking as these tasks will be completed once the virtual machine is up and running.
Repeat these steps as necessary to install the operating system on additional virtual machines.