Hi Jason,

Alluxio does work with Spark in master=local mode. This is because both
spark-submit and spark-shell have command-line options to set the classpath
for the JVM that is being started.

If you are not using spark-submit or spark-shell, you will have to figure
out how to configure that JVM instance with the proper properties.

Thanks,
Gene

On Fri, Apr 13, 2018 at 10:47 AM, Jason Boorn <jbo...@gmail.com> wrote:

> Ok thanks - I was basing my design on this:
>
> https://databricks.com/blog/2016/08/15/how-to-use-
> sparksession-in-apache-spark-2-0.html
>
> Wherein it says:
> Once the SparkSession is instantiated, you can configure Spark’s runtime
> config properties.
> Apparently the suite of runtime configs you can change does not include
> classpath.
>
> So the answer to my original question is basically this:
>
> When using local (pseudo-cluster) mode, there is no way to add external
> jars to the spark instance.  This means that Alluxio will not work with
> Spark when Spark is run in master=local mode.
>
> Thanks again - often getting a definitive “no” is almost as good as a
> yes.  Almost ;)
>
> On Apr 13, 2018, at 1:21 PM, Marcelo Vanzin <van...@cloudera.com> wrote:
>
> There are two things you're doing wrong here:
>
> On Thu, Apr 12, 2018 at 6:32 PM, jb44 <jbo...@gmail.com> wrote:
>
> Then I can add the alluxio client library like so:
> sparkSession.conf.set("spark.driver.extraClassPath", ALLUXIO_SPARK_CLIENT)
>
>
> First one, you can't modify JVM configuration after it has already
> started. So this line does nothing since it can't re-launch your
> application with a new JVM.
>
> sparkSession.conf.set("spark.executor.extraClassPath",
> ALLUXIO_SPARK_CLIENT)
>
>
> There is a lot of configuration that you cannot set after the
> application has already started. For example, after the session is
> created, most probably this option will be ignored, since executors
> will already have started.
>
> I'm not so sure about what happens when you use dynamic allocation,
> but these post-hoc config changes in general are not expected to take
> effect.
>
> The documentation could be clearer about this (especially stuff that
> only applies to spark-submit), but that's the gist of it.
>
>
> --
> Marcelo
>
>
>

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