Linux System Administration

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Chapter 9: Virtualization in the Modern Enterprise

The xm manpage gives the following example of a minimal guest, with a loopback

file image on the host appearing as the root device on the guest:

kernel = "/boot/vmlinuz-2.6-xenU"

memory = 128

name = "MyLinux"

root = "/dev/hda1 ro"

disk = [ "file:/var/xen/mylinux.img,hda1,w" ]

Once you have a guest configuration file, create the Xen guest with this command:

# xm create -c guest_name

where guest_name can be a full pathname or a relative filename (in which case Xen

places it in /etc/xen/

guest_name). Xen will create the guest domain and try to boot it

from the given file or device. The -c option attaches a console to the domain when it

starts, so you can answer the installation questions that appear.

Installing VMware

VMware has made its server available for free, and the code is even open source. You

can find it at http://www.vmware.com/products/server. We found it robust and user-

friendly. You can read about VMware’s open source and community source initia-

tives on its web site.

As we mentioned earlier, startups such as XenSource and Virtual Iron have taken

advantage of the Linux kernel’s support of hypervisor technology from IBM. Under

competitive pressure from Xen, VMware has also submitted its own open source

contributions to the kernel developers, realizing that VMware will run better on

Linux if VMware gives the Linux kernel a little help. ...