[Openstack] More than one compute_driver in nova.conf

Robert Collins robertc at robertcollins.net
Tue Aug 13 03:50:25 UTC 2013

On 13 August 2013 15:15, Jake G. <dj_dark_junglist at yahoo.com> wrote:
> I was wondering how to handle changing the compute_driver in nova.conf? I
> currently have the default
> compute_driver = libvirt.LibvirtDriver
> libvirt_type=kvm
> I want to be able to add the driver for baremetal provisioning, but I am
> unclear on how to do this.
> Can there be more than one compute_driver or do I have to replace
> compute_driver = libvirt.LibvirtDriver with the new driver.

You need to have a dedicated nova cell/region/cloud for baremetal. We
change the scheduler at a fairly fundamental layer - Devananda has
plans to rectify this, but probably only after Ironic is stable.

> If I can only replace what will happen to my existing KVM and nova
> operations?

I suggest spinning up a new host rather than modifying your existing one.

> Also, I am just using the bearmetal driver as an example. This same question
> can be applied to any other feature that requires a different
> compute_driver.

Baremetal is special - unlike lxc/kvm/qemu baremetal doesn't subdivide
an existing hypervisors resources, rather it hands out entire machines
- so it has to match exactly rather than matching a subset when
comparing flavors.


Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud

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