[openstack-dev] Blueprint for Nova native image building

Antony Messerli amesserl at rackspace.com
Tue Aug 6 20:45:50 UTC 2013

The patch referred to (https://review.openstack.org/#/c/38650/) isn't really around adding support to build native images.  We're using the existing boot from ISO support feature to load an iPXE ISO into Glance which then can then chain load a menu of installation options from an http server.  This allows us to "netboot" any operating system.  We're using it primarily with XenServer today but this method should work with all of the other hypervisors.

The goal of this specific patch is to provide support for Xen service providers that utilize static networking, so that customers of that service provider can utilize this tool without having to manually input the networking information of their instance.  The iPXE iso can be set in DHCP mode or require manual input of the address of the instance.  The patch automates the input without having to use DHCP by regenerating the ISO with the networking information required to bring the instance onto the network when in the virtual BIOS.

For providers using DHCP, no additional code is needed, just an iPXE iso registered into Glance.  It makes for a really handy way to provision a new image from scratch.


On Aug 6, 2013, at 2:02 PM, Monty Taylor <mordred at inaugust.com> wrote:

> On 08/06/2013 03:46 PM, Russell Bryant wrote:
>> On 08/06/2013 12:20 PM, Russell Bryant wrote:
>>> On 08/06/2013 11:53 AM, Ian Mcleod wrote:
>>>> Hello,
>>>> A blueprint has been registered regarding API additions to Nova to
>>>> enable the creation of base images from external OS install sources.
>>>> This provides a way to build images from scratch via native OS installer
>>>> tools using only the resources provided through Nova.  These images can
>>>> then be further customized by other tools that expect an existing image
>>>> as an input, such as disk image builder.
>>>> Blueprint -
>>>> https://blueprints.launchpad.net/nova/+spec/base-image-creation
>>>> Specification - https://wiki.openstack.org/wiki/NovaImageCreationAPI
>>>> If this is a topic that interests you, please have a look (the spec is
>>>> not very long) and join the conversation.
>>>> Please note that this blueprint follows on from proof of concept work
>>>> for native image building discussed on this list in April:
>>>> http://lists.openstack.org/pipermail/openstack-dev/2013-April/007157.html
>>> Thanks of the update on this work.
>>> I see that your proof of concept shows how this can work as a tool
>>> outside of Nova:
>>> https://github.com/redhat-openstack/image-building-poc
>>> So, my biggest question is whether or not it makes sense for this to be
>>> a Nova feature or not.  If something can be implemented as a consumer of
>>> Nova, my default answer is that it should stay outside of nova until I
>>> am convinced otherwise.  :-)
>>> It sounds like this is mostly an extension to nova that implements a
>>> series of operations that can be done just as well outside of Nova.  Are
>>> there enhancements you are making or scenarios that won't work at all
>>> unless it lives inside of Nova?
>>> If it doesn't end up on the server side, it could potentially be
>>> implemented as an extension to novaclient.
>> Also, whatever we end up with, I'd like to see it hypervisor agnostic as
>> much as possible.  I just came across this xen specific patch:
>> https://review.openstack.org/#/c/38650/
> Yes to everything Russel said. I'd like to see the tool be standalone.
> Then, if there is a desire to provide the ability to run it via an api,
> the tool could be consumed (similar discussions have happened around
> putting diskimage-builder behind a service as well)
> That said - if we did service-ify the tool, wouldn't glance be a more
> appropriate place for that sort of thing?
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