Open Stack

Excerpts from Erno Kuvaja's message of 2016-05-20 13:20:11 +0100:
> 
> The only reliable way to create Glance images for consumption in general
> manner is to make sure that we use the normal workflows (currently
> uploading the image to Glance and in future the supported manners of Image
> Import) and let Glance and Glance only to deal with it's backends.
> 

Sounds good to me, Glance needs to be the gateway for images, not
anything else.

I wonder if the shade library would be useful here.

If Heat were to use shade, which hides the complexities of not only
v1 vs v2, but also v2 with import vs. v2 with upload through glance,
then one could have a fairly generic image type.

Ansible has done this, which is quite nice, because now ansible users
can be confident that whatever OpenStack cloud they're interacting with,
they can just use the os_image module with the same arguments.

Anyway, if shade isn't used, Heat will need to do something similar,
which is to provide template users a way to port their templates to the
API's available. Perhaps the provider template system could be used so
each Heat operator can provide a single "image upload" template snippet
that gets used.

That would bring on a second question, which is how does one even upload
a large file to Heat. This is non-trivial, and I think the only way Heat
can reasonably support this is by handing the user a Swift tempurl in
the create/update stack API whenever a file is referenced. That swift
object would then be used by the engine to proxy that file into glance if
import isn't supported, or if it is, to tell glance where to import from.