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 >> > > > > >> > > > >> > > >> > >>
