====== KVM ======
===== Stack =====
  - **KVM (Kernel Virtual Machine)**: kernel module for user space programs to utilize the [[wp> Hardware-assisted_virtualization|HW virtualization features]]  of CPUs 
    * exposes ''/dev/kvm'' (CPU, memory, I/O, network, maps video display back to host...)
  -  **QEMU**: generic open source machine emulator and virtualizer
      * virtualizer: executes the guest code directly on the host CPU
      * userspace host using KVM (can also use Xen) 
      * falls back to software-only emulation without KVM
      * SeaBIOS: open source implementation of a 16-bit x86 BIOS
  - **libvirt**: open source API for platform virtualization (daemon and mgmt tool) 
       * manages KVM, QEMU (Xen, VMware ESX...) 
  - **virsh**: command line interface tool for managing guests and the hypervisor
     * built on libvirt


===== Virsh =====
==== Boot from CD ====
<code xml>
 <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/iso/CentOS-7.0-1406-x86_64-livecd.iso'/>
      <target dev='hdd'/>
      <readonly/>
 </disk>
</code>

<code xml>
<os>
    <boot dev='cdrom'/>
    <boot dev='hd'/>
    <bootmenu enable='yes'/>
</os>
</code>

==== Attach CD ====
<code bash>
virsh attach-disk domain1 /iso/CentOS-7.0-1406-x86_64-livecd.iso hdc --type cdrom --mode readonly
</code>