Why would you want to do this, when Xen can offer better performance than VMware? Portability – I can run a VMware virtual machine on Mac under VMware Fusion, on Windows under VMware Server, Workstation, or Player.

In my office, I’ve got a Dell Poweredge 830 with 8GB RAM, but my desktop computer is a Mac Mini which maxes out at 2GB RAM. It’s a no brainer to use the Dell for setting up the VM’s and then moving them to other machines when the time comes.

If your CentOS 5 box is running the xen kernel and try to install VMware Server 2.0 (currently in beta), you’ll get the following error when trying to install the RPM:

 You cannot install VMware Server on a system running a xen kernel

As a result, you need to switch to a non-xen kernel.

To do this, you first need to install the kernel. yum makes this easy:

yum install kernel

Then remove xen and the kernel-xen packages:

yum remove xen kernel-xen

Then you have to specify which kernel you want to run in /boot/grub/grub.conf. In that file there’s a list of kernels available to boot from:

#boot=/dev/sda
default=1
timeout=5
splashimage=(hd0,0)/boot/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-92.1.10.el5)
        root (hd0,0)
        kernel /boot/vmlinuz-2.6.18-92.1.10.el5 ro root=LABEL=/1 rhgb quiet
        initrd /boot/initrd-2.6.18-92.1.10.el5.img
title CentOS (2.6.18-92.1.10.el5xen)
        root (hd0,0)
        kernel /boot/xen.gz-2.6.18-92.1.10.el5
        module /boot/vmlinuz-2.6.18-92.1.10.el5xen ro root=LABEL=/1 rhgb quiet
        module /boot/initrd-2.6.18-92.1.10.el5xen.img

The line that says default= specifies which kernel to load, where 0 is the first one listed in the file. In my case, I had to change the line that says default=1 to default=0 to specify the non-xen kernel.

Reboot, and you’re good to go – the VMware RPM will install, and VMware server runs just fine.