Have you ever wished you had another computer handy? Maybe you want to
try a new operating system out. Maybe you want to test something
experimental without potentially breaking your own system. Maybe you
need to run some software that only runs in a different operating
system. Mandriva Linux 2007 Spring comes with a range of
virtualization options that can help.
Virtualization can often be the best way to handle these
situations. To put it simply, virtualization systems simulate a
complete running PC in software. You can install an operating
system
to the virtual machine without it being aware it is really just
running inside a program on your desktop. Virtualization systems
emulate all the important hardware on a PC, including the processor,
memory, disk drives, graphics card, sound card and monitor. The
operating system you install on the virtual machine is the real deal,
which means it will almost always work exactly the same way as it
would on a real computer.
There are several virtualization systems available for Linux, all of
which work a little differently and are good for different
purposes. Let's take the simplest option first. Imagine you run
Mandriva Linux 2007 Spring on your computer, but you need to test
something out on another Linux distribution. For simply running
one
other operating system on your computer occasionally, or another copy
of the same operating system for testing purposes, VirtualBox is the
best option. VirtualBox is an easy-to-use graphical virtualization
application, and it's quick and easy to set up and boot new VirtualBox
machines.
Mandriva Linux 2007 Spring Discovery, Powerpack and Powerpack+
editions include VirtualBox on the DVD. Just use the Mandriva software
installation tools to install the 'virtualbox' package. See this
Mandriva Wiki page
(
href="http://wiki.mandriva.com/en/Docs/Basic_tasks/Installing_and_removing_software"
target="_blank">http://wiki.mandriva.com/en/Docs/Basic_tasks/Installing_and_removing_software)
for instructions on installing packages. Mandriva Linux 2007 Spring One
and
Free editions do not include VirtualBox on the discs, but you can easily
install it from the official Internet repositories. See this Mandriva
wiki
page
(
href="http://wiki.mandriva.com/en/Docs/Basic_tasks/Installing_and_removing_software#Making_more_applications_available"
target="_blank">http://wiki.mandriva.com/en/Docs/Basic_tasks/Installing_and_removing_software#Making_more_applications_available)
for instructions on setting up the official repositories, then install
the
'virtualbox' package as described above.
Once you have VirtualBox installed, you can run it from the system
menus, under More Applications / Emulators. You will see the
VirtualBox control panel. Right now, there won't be any virtual
machines set up, so let's create one! Click on the New button. Click
Next. Now enter a name for your new virtual machine. This can be
anything you like: make it descriptive so you can recognize the
machine later. Set the OS Type box to whichever type of operating
system you intend to install on the virtual machine (for most modern
Linux distributions you would choose Linux 2.6). Now click Next. Next
you must set the amount of memory the virtual machine will have. This
memory will be allocated from free memory on your computer, so don't
set it any higher than the amount of free memory you have available,
or the virtual machine will run very slowly. However, remember to set
it higher than the minimum amount of memory required by the operating
system you are installing. It's best to stick to an amount of
memory
that is a power of two, as found on real computers: 64MB, 128MB, 256MB
and so on. Now click Next again. Now you must set up the hard disk for
the virtual machine. On your real computer, this will simply be a
single very big file. To create a new hard disk image file, click the
New... button. Click Next.
You can choose to use a dynamically expanding image (which will only
be as large as the actual amount of data it contains, no matter how
big you say the disk is) or a fixed-size image (which will be as big
as the capacity of the disk, even if there is very little data stored
on it). VirtualBox explains the benefits of each choice, so choose
appropriately and click Next. Now you can set how big the disk will be
and what the image file will be called. By clicking on the folder icon
next to the image file name you can set where it will be stored
(by default it is stored in a hidden folder in your home directory) -
make
sure you choose a location on a partition with enough free space to hold
whatever size of disk you choose! Now click Next again, and click
Finish.
You'll be back at the hard disk configuration dialog, but the new image
file
you created will be listed. Click Next, and a summary of the settings
you
chose will be displayed. Click Finish, and your virtual machine is
created!
It's not quite ready to be used yet, though. You might have noticed
that we didn't set up a CD / DVD drive, so it won't have anything to
boot from. Select your new virtual machine in the list in the main
VirtualBox window and click the Settings button. Click CD/DVD-ROM and
check the Mount CD/DVD Drive checkbox. You can choose to either use a
real CD/DVD drive on your real computer, or use a .ISO disc image file
which will be seen by the virtual machine as a real disc. In our
example, we'll go with the second option. Make sure you have a .ISO
image of the installer disc for the operating system you want to
install on the virtual machine. Select ISO Image File and click the
little folder icon at the right hand side. The Virtual Disk Manager
window will open, with the CD/DVD Images tab selected. Click the Add
button, then navigate to and select the .ISO image you want to use,
and click Open. Back in the other window, click Select. The window
will close and you'll see that the .ISO image you chose will be set to
be the CD/DVD for the virtual machine.
You can also set sound and network options from this window, but you
shouldn't need to change them for now, so click OK, and you'll be back
at the main window. Now you can boot your new virtual machine! Select
it from the list and click the Start button, and you will see a new
window appear and a typical PC boot process begin. From now on, this
window behaves just like a completely separate machine. The installer
for the operating system you chose will boot up, and you will be able
to go ahead and install it. For networking, set everything to
auto-detect, and an internet connection will be available for the
virtual machine. For the video card, use the framebuffer or VESA
compatibility driver. Note that you can 'grab' the mouse pointer and
keyboard into the VirtualBox window simply by clicking: now your mouse
will control the pointer on the VirtualBox machine and the keyboard
will type into the VirtualBox machine. To 'release' the pointer and
let your mouse and keyboard control your real computer again, just
press the right-hand side Control key on your keyboard.
There is much more to VirtualBox than explained in this starter
guide. For help with its more advanced options and features, take a
look at the documentation
(
href="http://www.virtualbox.org/wiki/End-user_documentation"
target="_blank">http://www.virtualbox.org/wiki/End-user_documentation)
on the
official site.
Besides VirtualBox, Mandriva Linux 2007 Spring includes some other
virtualization options.
Xen is a virtualization system aimed less at the desktop user and more
at server-level virtualization. Using Xen requires installing two
special kernel packages - one to be booted on the host machine, the
other to be used in the guest machines - and the creation of disk
images for the clients. Mandriva Linux 2007 Spring includes a tool
named drakvirt which can help configure and manage Xen
guests. drakvirt is included in the Powerpack and Powerpack+ editions
of Mandriva Linux 2007 Spring, and available from the official
Internet repositories for other editions. See the start of the
VirtualBox section for instructions on installing packages.
VMware is a commercial virtualization provider which provides many
different systems that cover the whole range of virtualization
requirements. Mandriva Linux 2007 Spring Powerpack and Powerpack+
editions include the VMware Player, a simple application which allows
you to 'play' - run - virtual machines created by other people using
the more advanced VMware products. Due to VMware's popularity within
the industry, many of these 'virtual appliances' are available,
ranging from full installations of many Linux distributions to very
specialized packages designed for a single purpose, such as a
pre-built package of a streamlined Linux distribution with a web
server stack running a particular web application. To install VMware
Player, simply use the Mandriva Linux software installation tools to
install the VMwarePlayer package. To find virtual machines to run on
it, take a look at the VMware Virtual Appliance Marketplace
(
href="http://www.vmware.com/vmtn/appliances/index.html" target="_blank">http://www.vmware.com/vmtn/appliances/index.html).
qemu is a long-standing Linux virtualization application which is very
flexible and powerful. To try out qemu quickly and easily, use the
Mandriva Linux software installation tools to install the 'qemu'
package. From a console, run this command to create a hard disk image:
qemu-img create disk.img 4G
4G specifies the size, 4GB. You can change it as appropriate. Now run
the following command:
qemu -cdrom image.iso -boot d disk.img
change 'image.iso' to the name of a .ISO image of an operating system
installation disc. This tells qemu to use image.iso as the CD/DVD
drive, boot from the CD/DVD, and use disk.img as the primary hard
disk. The virtual machine will boot into the operating system
installation routine. To learn more about using qemu, see the official
documentation
(
href="http://fabrice.bellard.free.fr/qemu/qemu-doc.html"
target="_blank">http://fabrice.bellard.free.fr/qemu/qemu-doc.html).
You can buy Mandriva Linux 2007 Spring Discovery, Powerpack and
Powerpack+ editions from the Mandriva Store
(
href="http://store.mandriva.com/" target="_blank">http://store.mandriva.com/).
Members of the Mandriva Club can download commercial editions of
Mandriva Linux 2007 Spring as part of their membership privileges:
join the Mandriva Club here
(
href="http://www.mandriva.com/en/community/resources/club"
target="_blank">http://www.mandriva.com/en/community/resources/club).
The Mandriva Linux 2007 Spring Free and Mandriva Linux 2007 Spring One
editions are available for free download from the Mandriva Linux
download page (
href="http://www.mandriva.com/en/download" target="_blank">http://www.mandriva.com/en/download).
Article published under Creative Commons Attribution 3.0 Unported
license.
Article written by Adam Williamson.
http://www.linuxlinks.com/portal/news/article.php?story=200705161241344