VirtualBox
ISO testing with VirtualBox
VirtualBox is a useful tool in testing ISO images since you can create imaginative disk configurations, erase or resize disks without concern for your system and test images while working normally on your machine. You can do the same thing with VMware Workstation but VirtualBox has a GPL version and can be used without a serial number.
Installing VirtualBox
Virtualbox OSE is included in Ubuntu's repository since Gutsy, so you now just have to install the "virtualbox-ose" package using synaptic, adept or one of the command line tools (sudo aptitude install virtualbox-ose). When using apt-get install the necessary kernel module won't be installed (recommended package virtualbox-ose-modules) automatically and you will need to install it afterwards.
In order to get access to the kernel module you have to add your user to the vboxusers group (created by the installer). Go to System -> Administration -> Users and Groups. Click Manage Groups and scroll down to the vboxusers group. Click Properties and add your user to it. Log out and back in for the group settings to take effect.
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Setting up a virtual machine
Click New to create a new Virtual Machine (VM). Follow the instructions on the [http://www.virtualbox.org/wiki/End-user_documentation VirtualBox site].
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Setting up VM hardware
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Give the VM a name and select Linux 2.6 as the OS. If you don't already have a virtual disk defined you need to create one.
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Select a dynamically expanding image. 3 GB is probably a good size. Less for Xubuntu or Ubuntu-server.
Mounting an ISO
You could burn the ISO to a CD and mount that in VirtualBox, but it's more conveniant to simply mount the ISO directly.
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Starting your VM
Click start to boot into your new VM. You should see the boot screen from the CD. Boot and install as normal. When installation is complete, reboot from within Ubuntu and the virtual CD should be automatically unmounted. If not, press F12 when VirtuLBox restarts the VM and select booting from the hard drive.
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Streamlining
You can set up the VMs as you test, but you can also set several machines up ahead of time. That way you can set up several machines, each with its own hardware configuration, linked to a virtual disk and an ISO image. Giving each VM it's own disk will require a good deal of free space on your test system, so you may want to share a generic disk for installs (just connect to it before starting a given VM).
If you have an rsync script on a cron job you can have the ISOs you intend to test downloaded overnight (or while you are away). The links from VirtualBox the the 'CD drive' (which you point to the rsync target) will stay mounted. When you want to test a given ISO you just start the pre-defined VM and VirtualBox will boot the freshly rsynced image. This is useful when testing the same case repeatedly and when time gets short closer to release.