[Discuss] gracefully shutdown guests

[cra at WPI.EDU (Chuck Anderson)]

> I never heard of this "libvirt" thing before today.  I spent
> something like an hour looking into it, couldn't figure out what the
> heck it's supposed to do, or how it's supposed to do it.  Decided to
> quit wasting time and move on...

It seems many people haven't heard of the built-in native
virtualization technology on Linux and it's management stack as
supported by Red Hat & developed and released first on Fedora.  It is
called KVM for Kernel-based Virtual Machine, and the userspace
component of it uses QEmu to provide the hardware access, BIOS
emulation, etc.  The whole thing is managed by the libvirtd daemon,
libvirt library, command shell virsh, and installer virt-install.
libvirt actually supports managing KVM, Xen, QEmu, LXC, OpenVZ,
VirtualBox and VMware ESX (or so the virsh manpage claims).

There is a GUI front-end called virt-manager (which uses virt-viewer
to provide a graphical console to the VM over SPICE or VNC) which can
manage local or remote VMs.  By default VM disk images are stored in
/var/lib/libvirt/images or in your home directory under
VirtualMachines.

If you are looking for the closest equivalent to a VirtualBox- or
VMware-sytle desktop virtualization interface, try running
virt-manager (called "Virtual Machine Manager" in the desktop menu) or
a new GNOME 3 front-end called "Boxes" (though this is still fairly
rough around the edges being so new).

There are also a bunch of nice utilities in the libguestfs-tools,
virt-v2v, virt-p2v, and virt-top packages.  With these you can inspect
and manipulate guest disk images, convert one virtual machine type
into another, convert a physical machine to a virtual one, etc.

There are yum groups for the various pieces:

   Virtualization
   Virtualization Client
   Virtualization Platform
   Virtualization Tools

Do "yum groupinstall Virtualization" etc. to get this stuff installed.

For Fedora or Red Hat systems, the native virtulization stack is
arguably going to be better integrated with the system to support
things like shutting down guests gracefully, etc.