33.2. Changing between the KVM and Xen hypervisors
This section covers changing between the KVM and Xen hypervisors.
Red Hat only supports one active hypervisor at a time.
Important
Presently, there is no application for switching Xen-based guests to KVM or KVM-based guests to Xen.
Warning
This procedure is only available for the Intel 64 or AMD64 version of Red Hat Enterprise Linux 5.4 or newer. No other configurations or Red Hat Enterprise Linux versions are supported. KVM is not available in versions earlier than Red Hat Enterprise Linux 5.4.
33.2.1. Xen to KVM 复制链接链接已复制到粘贴板!
复制链接链接已复制到粘贴板!
The following procedure covers changing from the Xen hypervisor to the KVM hypervisor. This procedure assumes the kernel-xen package is installed and enabled.
Install the KVM package
Install the kvm package if you have not already done so.yum install kvm
# yum install kvm
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Verify which kernel is in use
The kernel-xen package may be installed. Use theuname
command to determine which kernel is running:uname -r
$ uname -r 2.6.18-159.el5xen
Copy to Clipboard Copied! Toggle word wrap Toggle overflow The present kernel, "2.6.18-159.el5xen
", is running on the system. If the default kernel, "2.6.18-159.el5
", is running you can skip the substep.Changing the Xen kernel to the default kernel
Thegrub.conf
file determines which kernel is booted. To change the default kernel edit the/boot/grub/grub.conf
file as shown below.Copy to Clipboard Copied! Toggle word wrap Toggle overflow Notice the default=1 parameter. This is instructing the GRUB boot loader to boot the second entry, the Xen kernel. Change the default to0
(or the number for the default kernel):Copy to Clipboard Copied! Toggle word wrap Toggle overflow
Reboot to load the new kernel
Reboot the system. The computer will restart with the default kernel. The KVM module should be automatically loaded with the kernel. Verify KVM is running:lsmod | grep kvm
$ lsmod | grep kvm kvm_intel 85992 1 kvm 222368 2 ksm,kvm_intel
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Thekvm
module and either thekvm_intel
module or thekvm_amd
module are present if everything worked.
33.2.2. KVM to Xen 复制链接链接已复制到粘贴板!
复制链接链接已复制到粘贴板!
The following procedure covers changing from the KVM hypervisor to the Xen hypervisor. This procedure assumes the kvm package is installed and enabled.
Install the Xen packages
Install the kernel-xen and xen package if you have not already done so.yum install kernel-xen xen
# yum install kernel-xen xen
Copy to Clipboard Copied! Toggle word wrap Toggle overflow The kernel-xen package may be installed but disabled.Verify which kernel is in use
Use theuname
command to determine which kernel is running.uname -r
$ uname -r 2.6.18-159.el5
Copy to Clipboard Copied! Toggle word wrap Toggle overflow The present kernel, "2.6.18-159.el5
", is running on the system. This is the default kernel. If the kernel hasxen
on the end (for example,2.6.18-159.el5xen
) then the Xen kernel is running and you can skip the substep.Changing the default kernel to the Xen kernel
Thegrub.conf
file determines which kernel is booted. To change the default kernel edit the/boot/grub/grub.conf
file as shown below.Copy to Clipboard Copied! Toggle word wrap Toggle overflow Notice the default=0 parameter. This is instructing the GRUB boot loader to boot the first entry, the default kernel. Change the default to1
(or the number for the Xen kernel):Copy to Clipboard Copied! Toggle word wrap Toggle overflow
Reboot to load the new kernel
Reboot the system. The computer will restart with the Xen kernel. Verify with theuname
command:uname -r
$ uname -r 2.6.18-159.el5xen
Copy to Clipboard Copied! Toggle word wrap Toggle overflow If the output hasxen
on the end the Xen kernel is running.