Open Stack

Excerpts from Jim Rollenhagen's message of 2016-11-04 10:50:34 -0400:
> On Thu, Nov 3, 2016 at 3:04 PM, Joshua Harlow <harlowja at fastmail.com> wrote:
> > Jay Faulkner wrote:
> >>>
> >>> On Nov 3, 2016, at 11:27 AM, Joshua Harlow<harlowja at fastmail.com>  wrote:
> >>>
> >>> Just as a followup from the summit,
> >>>
> >>> One of the sessions (the new lib one) had a few proposals:
> >>>
> >>> https://etherpad.openstack.org/p/ocata-oslo-bring-ideas
> >>>
> >>> And I wanted to try to get clear owners for each part (there was some
> >>> followup work for each); so just wanted to start this email to get the
> >>> thoughts going on what to do for next steps.
> >>>
> >>> *A hash ring library*
> >>>
> >>> So this one it feels like we need at least a tiny oslo-spec for and for
> >>> someone to write down the various implementations, what they share, what
> >>> they do not share (talking to swift, nova, ironic and others? to figure this
> >>> out). I think alexis was thinking he might want to work through some of that
> >>> but I'll leave it for him to chime in on that (or others feel free to also).
> >>>
> >>> This one doesn't seem very controversial and the majority of the work is
> >>> probably on doing some analysis of what exists and then picking a library
> >>> name and coding that up, testing it, and then integrating (pretty standard).
> >>>
> >>
> >> Ironic and Nova both share a hash ring implementation currently
> >> (ironic-conductor and nova-compute driver for ironic). It would be sensible
> >> to reuse this implementation, oslo-ify it, and have that code shared.
> >>
> >> I question the value of re-implementing something like this from scratch
> >> though.
> >>
> >> Thanks,
> >> Jay Faulkner
> >> OSIC
> >>
> >
> > Right I don't think the intention would be to implement it from scratch, but
> > to do some basic analysis of what exists (and think about and document the
> > patterns), and try to find the common parts (which likely involves renaming
> > some specific nova/ironic methods from what I see); especially if we can get
> > swift to perhaps (TBD) also use and contribute to this library.
> 
> As the person who copied that code into Nova, the Nova code is a strict subset
> of the Ironic code.
> 
> Some of us talked to John Dickinson off-list, and it seems the Swift hash ring
> has very different use cases and very different implementation. I
> think we should
> focus on pulling the Nova/Ironic code out first, and then talking to
> Swift if we can
> also make it work for them (sounds like it's not helpful today).
> 
> // jim
> 

Thanks for the background, Jim. I thought the code shared more with
Swift's implementation than it sounds like it does, so I agree with your
proposed plan.

Doug