Only the API methods on the scheudler; i propose that the client adopt the scheduler's update orchestration and we delete the equivalent code from the client.
-=Bill On Fri, Jul 25, 2014 at 3:54 PM, Maxim Khutornenko <ma...@apache.org> wrote: > I am a bit confused. Are you suggesting we retain the current client > updater algorithm or only the scheduler primitives it currently > employs? > > On Fri, Jul 25, 2014 at 3:36 PM, Bill Farner <wfar...@apache.org> wrote: > > Yeah, absolutely - we will retain AURORA-383 > > <https://issues.apache.org/jira/browse/AURORA-383> for that. > > > > -=Bill > > > > > > On Fri, Jul 25, 2014 at 2:48 PM, Brian Wickman <wick...@apache.org> > wrote: > > > >> The scheduler API should know when jobs are locked, though, right? That > >> information could be made available to the UI. > >> > >> > >> On Fri, Jul 25, 2014 at 2:40 PM, Bill Farner <wfar...@apache.org> > wrote: > >> > >> > I think the current API primitives used for updates (kill, add) will > >> > continue to make sense, so a client could implement updates that way. > >> > However, these will not appear as updates to the scheduler. > >> > > >> > -=Bill > >> > > >> > > >> > On Fri, Jul 25, 2014 at 2:31 PM, Maxim Khutornenko <ma...@apache.org> > >> > wrote: > >> > > >> > > Retaining client update algorithm would require extra work on the > >> > scheduler > >> > > side to satisfy visibility requirements Bill outlined above, which > may > >> > not > >> > > worth the effort. That would also create ground for inconsistent > update > >> > > expectations and experience. > >> > > > >> > > > >> > > On Fri, Jul 25, 2014 at 1:34 PM, Brian Wickman <wick...@apache.org> > >> > wrote: > >> > > > >> > > > Will the API for client-side updates still exist? Will the client > >> > > continue > >> > > > to have its own implementation of 'update' (or perhaps an 'update > >> > > --local' > >> > > > flag?) The reason I ask is whether customers should continue to > have > >> > the > >> > > > flexbility to implement their own update algorithms (e.g. 1% -> > 10% > >> -> > >> > > 25% > >> > > > -> 25% -> 25% -> rest.) > >> > > > > >> > > > > >> > > > On Fri, Jul 25, 2014 at 11:41 AM, Bill Farner <wfar...@apache.org > > > >> > > wrote: > >> > > > > >> > > > > Hi all, > >> > > > > > >> > > > > Rolling updates of services is a crucial feature in Aurora. As > >> such, > >> > we > >> > > > > want to take great care when changing its behavior. Today, > Aurora > >> > > > operates > >> > > > > by delegating this functionality to the client (or any API > client, > >> > for > >> > > > that > >> > > > > matter). While this has provided a nice abstraction, it turns > out > >> > there > >> > > > are > >> > > > > some shortcomings with this approach: > >> > > > > > >> > > > > 1. Visibility: since the scheduler does not know about > updates, > >> it > >> > > > cannot > >> > > > > display useful information about an in-progress update > >> > > > > 2. Visibility: for two users to diagnose a failed update, they > >> must > >> > > be > >> > > > at > >> > > > > the same terminal, or copy/paste terminal output > >> > > > > 3. Usability: the scheduler has no means to show information > >> about > >> > > how > >> > > > an > >> > > > > application's packages or configuration changed over time > >> > > > > 4. Usability: update orchestration in the client means a lost > >> > > > connection > >> > > > > to the scheduler halts an update > >> > > > > > >> > > > > Some of the above issues can be addressed by moving update > >> > > orchestration > >> > > > to > >> > > > > a service external to the scheduler. At first glance, this > approach > >> > is > >> > > > > attractive, as there is a firm separation of concerns. However, > >> there > >> > > > are a > >> > > > > few pitfalls with this approach: > >> > > > > > >> > > > > 1. Usability: setup and maintenance of an aurora cluster > becomes > >> > even > >> > > > > more complicated (additional service + storage system) > >> > > > > 2. Usability: the user interface becomes more complicated to > >> stitch > >> > > > > together, as end-users really should only have to visit one > website > >> > to > >> > > > view > >> > > > > job information. > >> > > > > 3. Complexity: implementing a new production-ready service > from > >> > > scratch > >> > > > > will take a non-trivial amount of time > >> > > > > > >> > > > > With these issues in mind, I propose that the scheduler take > over > >> the > >> > > > > responsibility of application update orchestration. This will > allow > >> > us > >> > > to > >> > > > > solve the current design shortcomings, without the pitfalls of > the > >> > > > separate > >> > > > > service approach. > >> > > > > > >> > > > > I'm interested in thoughts others have on this. Does the > reasoning > >> > seem > >> > > > > sound? Are there things i'm missing? > >> > > > > > >> > > > > > >> > > > > -=Bill > >> > > > > > >> > > > > >> > > > >> > > >> >
