[CentOS-virt] Preferred method of provisioning VM images

Thu Jun 12 16:25:43 UTC 2014
Ed Heron <Ed at Heron-ent.com>

On Tue, 2014-06-10 at 17:21 +0100, Lars Kurth wrote:
> Hi all,
> following the discussion on about documentation, I was wondering whether 
> we need to look at a standard way in which we recommend how to provision 
> images for VMs. Am starting this with a Xen hat, but the discussion 
> should not be specific to this. There are a number of options, but all 
> have some trade-offs
> == #1 virt-install ==
> Advantages: similar to KVM
> Disadvantages: may cause weird issues / confusion with people switching 
> back to xl. The core issue is that with the current version of xen and 
> libvirt, this only works with xm (when xl is used, this can create some 
> undefined behavior). However as we have seen in some recent threads on 
> this list, people tend to mix which can cause problems.
> ...

  I've chosen the virt-install method on CentOS 5 precisely because it
is like KVM.  I was hoping it would fulfill the promise of being
hypervisor agnostic.  I'm hoping it continues to be available on future
versions of CentOS with Xen.

  Though it is a waste of resources, I make all my virtual machines,
Linux and MS Windows alike, fully virtualized.  I can then move any of
the VM's with the same virt-install --import or virsh dumpxml/edit/virsh
define process.

  When moving a VM, usually the only thing I have to do outside of
virt-install/virt-manager is add <acpi/>, <apic/> or <pae/>, which can
be done with virsh edit.  I don't know why some of my virtual servers
need them and other don't but I have higher priority things to think

  I'm the only technical support person and I don't work 24/7.  The
graphical interface of virt-manager makes it possible for non-tech
people to see what is running and see consoles to restart any
misbehaving VM's (usually MS Windows VM's).

  I have completely eliminated my use of xm.