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From Mayur Rustagi <>
Subject Re: Quality of documentation (rant)
Date Sun, 19 Jan 2014 14:36:35 GMT
You an run Spark independent of hadoop, but that is a lie :) it is a big
confusing. Short fuse to all your problems would be to use CDH if you have
that choice and are starting a cluster. They bundle in spark assisted by
data bricks. Its ride should be a little smoother atleast from install and
pre-built library perspective.

If you are free to start your own cluster another good gratifying
experience is to use spark-ec2 tools. They are pretty well built and you
should have a cluster ready within an hr or so. I guess the image is pretty
well maintained and runs well.

Hadoop has 2 parts HDFS(Storage) and Yarn(processing). Spark has
independent processing engine as well as yarn integrated processing engine
as well as SIMR (spark on map reduce for hadoop 1.0). All of these take
files from HDFS, hence even when spark doesnt need hadoop it relies on
hdfs, The entire process is not really well documented and the lingo used
is also not very clear. Application->Stage-> task  etc. There was a lot of
good discussion in Spark Summit 2014 videos. Last I am trying to setup
documentation steps and a distribution around spark  in You are free to contribute and help me out. Just
drop me a mail.


Mayur Rustagi
Ph: +919632149971
h <>ttp://

On Sun, Jan 19, 2014 at 6:55 PM, Ankur Chauhan <>wrote:

> Hi ognen,
> I am in the same boat as you are. I actually work on a project that
> basically does this exact same thing and tried to aggregations by spark but
> it ended up with me trying again and again to do simple things like reading
> from s3 and such and failing.
> I have a little bit of knowledge about spark so I may be able to answer
> some basic stuff. (I just gave up on spark after wasting 2-3 weeks on it).
> Plus reading through the code is of little or no use as there is mostly no
> comments anywhere relevant and the scala syntax is pretty unintuitive for
> me.
> I would be more than happy to assist and work on documentation with you.
> Do you have any ideas on how you want to go about it or some existing plans?
> -- Ankur
> > On Jan 19, 2014, at 4:52, Ognen Duzlevski <>
> wrote:
> >
> > Hello,
> >
> > I have been trying to set up a running spark cluster for a while now.
> Being new to all this, I have tried to rely on the documentation, however,
> I find it sorely lacking on a few fronts.
> >
> > For example, I think it has a number of built-in assumptions about a
> person's knowledge of Hadoop or Mesos. I have been using and programming
> computers for almost two decades so I don't think I am a total idiot when
> it comes to these things, however, I am left with staring at the console
> wondering what the hell is going on.
> >
> > For example, the thing supports using S3 to get files but when you
> actually try to read a large file, it just sits there and sits there and
> eventually comes back with an error that really does not tell me anything
> (so the task was killed - why? there is nothing in the logs). So, do I
> actually need an HDFS setup over S3 so it can support block access? Who
> knows, I can't find anything.
> >
> > Even basic questions I have to ask on this list - does Spark support
> parallel reads from files in a shared filesystem? Someone answered - yes.
> Does this extend to S3? Who knows? Nowhere to be found. Does it extend to
> S3 only if used through HDFS? Who knows.
> >
> > Does Spark need a running Hadoop cluster to realize its full potential?
> Who knows, it is not stated explicitly anywhere but any time I google stuff
> people mention Hadoop.
> >
> > Can Spark do EVERYTHING in standalone mode? The documentation is not
> explicit but it leads you to believe it can (or maybe I am overly
> optimistic?).
> >
> > So what does one do when they have a problem? How do they instrument
> stuff?
> >
> > I do not want to just rant - I am willing to put work into writing
> proper documentation for something that is advertised to work but in
> practice ends up costing you weeks of hunting for crap left and right and
> feeling lost. I am going through this process and would be happy to
> document a whole story of setting up a data analysis pipeline from
> aggregating data via https exposed over an ELB to sending it to a spark
> cluster via zeromq collectors to actual Spark cluster setup to.... - is
> anyone willing to help answer my questions so we can all benefit from this
> "hair-greying" experience? ;)
> >
> > Thanks!
> > Ognen
> >
> >

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