KVM is a robust virtualization technology, strongly supported by Red Hat and easily scaled up to commercial levels of use on CentOS or RHEL. These notes are aimed at generic installation of CentOS 6 or RHEL 6 for such servers, aimed specifically at TUSK 4 or OpenTUSK.
RHEL requires a license, and DVD installation media. It's possible to do with a network boot CD and local RHEL mirror, but setting that up is beyond the scope of these notes.
CentOS can be installed with installation DVD's, or with a the CentOS-6.3-x86_64-netinstall.iso CD image from a local mirror and the URL of a local CentOS mirror. That's easier, but also beyond the scope of these notes.
Software RAID can work, but it's awkward. Server hardware should support hardware RAID, and it's invaluable when a disk fails on a virtualization server.
RHEL 6 or CentOS 6 is strongly preferred to CentOS 5 for this hypervisor, and x86_64 is absolutely necessary to be able to virtualize both i386 and x86_64 guests.
It's much easier to install RHEL 6 or CentOS with the "kickstart" tool, if network access is available when installing the host.
linux ksdevice=eth0 ip=[ipaddress] netmask=[netmask] gateway=[gateway] dns=[dns-server] ks=http://down.tusk.tufts.edu/ks/kvm-server.cfg
If an external network is unavailable, or if your server is on trunked VLAN's, kickstart will not be available. Review the kickstart file listed above, and follow these manual steps.
Configuring KVM bridges, especially with pair bonding is a manual process.
If your environment uses tagged VLAN's, see:
Note that taged VLAN's are not suggested: if you need multiple VLAN's, it's sually safer and more reliable to install additional network ports and use pairs of network ports for individual VLAN's.
For normal KVM hypervisor environments, see:
Critical software for running KVM is in the kickstart file, but for manual OS installations needs to be installed by hand. Run these commands to install them.
yum -y install libvirt yum -y install qemu-img yum -y install qemu-kvm yum -y install qemu-kvm-tools yum -y install virt-manager yum -y install virt-viewer yum -y install xorg-x11-xauth # Allows X sessions over SSH
KVM based virtual hosts can be migrated from one KVM server to another, with the host live, if they have a shared space to store the DISK images. This setup depends heavily on the local storage environment, but the obvious place to mount the storage is at /var/lib/libvirt/images, where KVM expects to find them.