Thank you for bringing this up, Trevor. EDP gets more diverse and it's time to change its model. I totally agree with your proposal, but one minor comment. Instead of "savanna." prefix in job_configs wouldn't it be better to make it as "edp."? I think "savanna." is too more wide word for this.
And one more bureaucratic thing... I see you already started implementing it [1], and it is named and goes as new EDP workflow [2]. I think new bluprint should be created for this feature to track all code changes as well as docs updates. Docs I mean public Savanna docs about EDP, rest api docs and samples. [1] https://review.openstack.org/#/c/69712 [2] https://blueprints.launchpad.net/openstack/?searchtext=edp-oozie-streaming-mapreduce Regards, Alexander Ignatov On 28 Jan 2014, at 20:47, Trevor McKay <tmc...@redhat.com> wrote: > Hello all, > > In our first pass at EDP, the model for job settings was very consistent > across all of our job types. The execution-time settings fit into this > (superset) structure: > > job_configs = {'configs': {}, # config settings for oozie and hadoop > 'params': {}, # substitution values for Pig/Hive > 'args': []} # script args (Pig and Java actions) > > But we have some things that don't fit (and probably more in the > future): > > 1) Java jobs have 'main_class' and 'java_opts' settings > Currently these are handled as additional fields added to the > structure above. These were the first to diverge. > > 2) Streaming MapReduce (anticipated) requires mapper and reducer > settings (different than the mapred.xxxx.class settings for > non-streaming MapReduce) > > Problems caused by adding fields > -------------------------------- > The job_configs structure above is stored in the database. Each time we > add a field to the structure above at the level of configs, params, and > args, we force a change to the database tables, a migration script and a > change to the JSON validation for the REST api. > > We also cause a change for python-savannaclient and potentially other > clients. > > This kind of change seems bad. > > Proposal: Borrow a page from Oozie and add "savanna." configs > ------------------------------------------------------------- > I would like to fit divergent job settings into the structure we already > have. One way to do this is to leverage the 'configs' dictionary. This > dictionary primarily contains settings for hadoop, but there are a > number of "oozie.xxx" settings that are passed to oozie as configs or > set by oozie for the benefit of running apps. > > What if we allow "savanna." settings to be added to configs? If we do > that, any and all special configuration settings for specific job types > or subtypes can be handled with no database changes and no api changes. > > Downside > -------- > Currently, all 'configs' are rendered in the generated oozie workflow. > The "savanna." settings would be stripped out and processed by Savanna, > thereby changing that behavior a bit (maybe not a big deal) > > We would also be mixing "savanna." configs with config_hints for jobs, > so users would potentially see "savanna.xxxx" settings mixed with oozie > and hadoop settings. Again, maybe not a big deal, but it might blur the > lines a little bit. Personally, I'm okay with this. > > Slightly different > ------------------ > We could also add a "'savanna-configs': {}" element to job_configs to > keep the configuration spaces separate. > > But, now we would have 'savanna-configs' (or another name), 'configs', > 'params', and 'args'. Really? Just how many different types of values > can we come up with? :) > > I lean away from this approach. > > Related: breaking up the superset > --------------------------------- > > It is also the case that not every job type has every value type. > > Configs Params Args > Hive Y Y N > Pig Y Y Y > MapReduce Y N N > Java Y N Y > > So do we make that explicit in the docs and enforce it in the api with > errors? > > Thoughts? I'm sure there are some :) > > Best, > > Trevor > > > > > > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
