On Mon, Aug 24, 2020 at 1:52 PM Sean Mooney <smooney@redhat.com> wrote:

On Mon, 2020-08-24 at 10:32 +0200, Dmitry Tantsur wrote:
> Hi,
>
> On Mon, Aug 24, 2020 at 10:24 AM Arne Wiebalck <arne.wiebalck@cern.ch>
> wrote:
>
> > Hi!
> >
> > CERN's deployment is using the iscsi deploy interface since we started
> > with Ironic a couple of years ago (and we installed around 5000 nodes
> > with it by now). The reason we chose it at the time was simplicity: we
> > did not (and still do not) have a Swift backend to Glance, and the iscsi
> > interface provided a straightforward alternative.
> >
> > While we have not seen obscure bugs/issues with it, I can certainly back
> > the scalability issues mentioned by Dmitry: the tunneling of the images
> > through the controllers can create issues when deploying hundreds of
> > nodes at the same time. The security of the iscsi interface is less of a
> > concern in our specific environment.
> >
> > So, why did we not move to direct (yet)? In addition to the lack of
> > Swift, mostly since iscsi works for us and the scalability issues were
> > not that much of a burning problem ... so we focused on other things :)
> >
> > Here are some thoughts/suggestions for this discussion:
> >
> > How would 'direct' work with other Glance backends (like Ceph/RBD in our
> > case)? If using direct requires to duplicate images from Glance to
> > Ironic (or somewhere else) to be served, I think this would be an
> > argument against deprecating iscsi.
> >
>
> With image_download_source=http ironic will download the image to the
> conductor to be able serve it to the node. Which is exactly what the iscsi
> is doing, so not much of a change for you (except for s/iSCSI/HTTP/ as a
> means of serving the image).
>
> Would it be an option for you to test direct deploy with
> image_download_source=http?
i think if there is still an option to not force deployemnt to altere any of there
other sevices this is likely ok but i think the onious shoudl be on the ironic
and ooo teams to ensure there is an upgrade path for those useres before this deprecation
becomes a removal without deploying swift or a swift compatibale api e.g. RadosGW

Swift is NOT a requirement (nor is RadosGW) when image_download_source=http is used. Any glance backend (or no glance at all) will work.