w ire compatibility is relevant if hadoop is included in spark build
for those of us that build spark without hadoop included hadoop (binary) api compatibility matters. i wouldn't want to build against hadoop 2.7 and deploy on hadoop 2.6, but i am ok the other way around. so to get the compatibility with all the major distros and cloud providers building against hadoop 2.6 is currently the way to go. On Thu, Feb 8, 2018 at 5:09 PM, Marcelo Vanzin <van...@cloudera.com> wrote: > I think it would make sense to drop one of them, but not necessarily 2.6. > > It kinda depends on what wire compatibility guarantees the Hadoop > libraries have; can a 2.6 client talk to 2.7 (pretty certain it can)? > Is the opposite safe (not sure)? > > If the answer to the latter question is "no", then keeping 2.6 and > dropping 2.7 makes more sense. Those who really want a > Hadoop-version-specific package can override the needed versions in > the command line, or use the "without hadoop" package. > > But in the context of trying to support 3.0 it makes sense to drop one > of them, at least from jenkins. > > > On Thu, Feb 8, 2018 at 2:03 PM, Sean Owen <so...@cloudera.com> wrote: > > That would still work with a Hadoop-2.7-based profile, as there isn't > > actually any code difference in Spark that treats the two versions > > differently (nor, really, much different between 2.6 and 2.7 to begin > with). > > This practice of different profile builds was pretty unnecessary after > 2.2; > > it's mostly vestigial now. > > > > On Thu, Feb 8, 2018 at 3:57 PM Koert Kuipers <ko...@tresata.com> wrote: > >> > >> CDH 5 is still based on hadoop 2.6 > >> > >> On Thu, Feb 8, 2018 at 2:03 PM, Sean Owen <so...@cloudera.com> wrote: > >>> > >>> Mostly just shedding the extra build complexity, and builds. The > primary > >>> little annoyance is it's 2x the number of flaky build failures to > examine. > >>> I suppose it allows using a 2.7+-only feature, but outside of YARN, not > >>> sure there is anything compelling. > >>> > >>> It's something that probably gains us virtually nothing now, but isn't > >>> too painful either. > >>> I think it will not make sense to distinguish them once any Hadoop > >>> 3-related support comes into the picture, and maybe that will start > soon; > >>> there were some more pings on related JIRAs this week. You could view > it as > >>> early setup for that move. > >>> > >>> > >>> On Thu, Feb 8, 2018 at 12:57 PM Reynold Xin <r...@databricks.com> > wrote: > >>>> > >>>> Does it gain us anything to drop 2.6? > >>>> > >>>> > On Feb 8, 2018, at 10:50 AM, Sean Owen <so...@cloudera.com> wrote: > >>>> > > >>>> > At this point, with Hadoop 3 on deck, I think hadoop 2.6 is both > >>>> > fairly old, and actually, not different from 2.7 with respect to > Spark. That > >>>> > is, I don't know if we are actually maintaining anything here but a > separate > >>>> > profile and 2x the number of test builds. > >>>> > > >>>> > The cost is, by the same token, low. However I'm floating the idea > of > >>>> > removing the 2.6 profile and just requiring 2.7+ as of Spark 2.4? > >> > >> > > > > > > -- > Marcelo >
