[Ovirt-devel] Question about ovirt migration

Perry N. Myers pmyers at redhat.com
Mon Sep 8 12:30:01 UTC 2008

Chris Lalancette wrote:
> Atsushi SAKAI wrote:
>> Hi, Chris
>> Thank you for your description.
>> Then I want to understand the software layer for *fake* managed node.
>> But, Nested KVM does not support at this moment.(Ref)
>> Would you point the code of guest boot on fake managed node?
>> Ref.
>> [PATCH 0/9] [RFC] Add support for nested SVM (kernel)
>> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/21119
> No, no.  We aren't using this at all (it's not in KVM at the moment, I don't
> think, and even if it was, there is no reason to use it in our case).  What
> happens is that when we install the WUI appliance, we also "install" 3 fake
> managed nodes alongside the WUI appliance.  These are basically just libvirt XML
> files, that will PXE boot when you start them up.  So, what happens is that you
> boot up the WUI appliance; once that is up, you can boot up your fake managed
> nodes.  Each of these fake managed nodes appears in the WUI as Hosts where you
> can start guests.  And, indeed, you can start guests inside of them; however,
> the guests inside of them are fully emulated only (not KVM accelerated), because
> we aren't using the nested SVM type stuff.
> In point of fact, the nested SVM stuff isn't really interesting to us; the whole
> point of ovirt is to manage physical hardware.  So the fake managed nodes are
> just a useful abstraction to let people who have limited hardware at least see
> what ovirt can do.

A further point...  We are in the process of trying to get rid of the 
'fake' oVirt Nodes.  Instead of using fake Nodes, the oVirt Server will be 
able to manage:
1. Real physical hosts running the oVirt Node from PXE or USB boot
2. Real HW accelerated VMs running directly on the same host that runs the
    oVirt Appliance.

In the case of #1 oVirt Server will be managing the oVirt Node (aka the 
Embedded Hypervisor)
In the case of #2 oVirt Server will be managing a Fedora 9 host that has 
the oVirt Node RPM installed on it, to convert a stock Fedora 9 host into 
something that oVirt can manage.

The 'fake' Nodes that we've been using up until now have been a developer 
convenience and were never meant to be used in production environments. 
They will be deprecated in favor of using methods #1 and #2 above.



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