> > the outdated instance count problem will only get worse as automated > scaling tools will quickly render existing .aurora config value obsolete
This is not a compelling reason to remove functionality. Sounds like a safeguard is needed instead. On Fri, Feb 5, 2016 at 2:43 PM, Maxim Khutornenko <ma...@apache.org> wrote: > This is mostly a survey rather than a proposal. How would people think > about limiting updater to only adding/updating instances and let > killTasks take care of instance removals? > > We have all heard stories (or happen to create some ourselves) when an > outdated instance count value in .aurora config caused unexpected > instance removals. Granted, there are plenty of other values in the > config that can cause service-wide outage but instance count seems to > be the worst in that sense. > > After the recent refactoring of addInstances and killTasks to act as > scaleOut/scaleIn APIs [1], the outdated instance count problem will > only get worse as automated scaling tools will quickly render existing > .aurora config value obsolete. With that in mind, should we block > instance removal in the updater and let an explicit killTasks call be > the only acceptable action to reduce instance count? Is there any > value (aside from arguable convenience factor) in having > startJobUpdate ever killing instances? > > Thanks, > Maxim > > [1] - http://markmail.org/message/2smaej5n5e54li3g >
