Red Hat Knowledgebase

If Virtualization was not selected during the installation of Red Hat Enterprise Linux 5, the Xen packages will need to be installed manually. The simplest way of accomplishing this is by having the machine registered to the Red Hat Network. First confirm that the server has a virtualization entitlement and is subscribed to the virtualization channel in RHN. Then install the required packages:

# yum install kernel-xen virt-manager xen

Make sure that kernel-xen is the default kernel to boot within the GRUB configuration file, /boot/grub/grub.conf. The default line indicates which kernel will be booted by default. This value is an integer corresponding to one of the title entries in the list of boot options, with the first boot entry being 0.

The Xen daemon service should also be set to start automatically upon boot - otherwise it will need to be manually started before any management or use of virtual machines. To enable xend to automatically start at runlevels 3 and 5:

# chkconfig xend on

Now reboot the machine and it should boot into the Xen kernel. To confirm this, check the name of the currently running kernel. The Xen management interface, xm, should also indicate that Domain-0 (the Xen host) is running:

# uname -r
# xm list

The operating system is now ready to create and host guest virtual machines. For a graphical interface with step-by-step instructions on creating guests, launch virt-manager:

# virt-manager

More information can be found in the Red Hat Enterprise Linux Virtualization Guide, available at http://www.redhat.com/docs/manuals/enterprise/