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Subject [DISCUSS] Spark-Kernel Incubator Proposal
Date Fri, 13 Nov 2015 00:17:42 GMT
Hello, we would like to start a discussion on accepting the Spark-Kernel,
a mechanism for applications to interactively and remotely access Apache
Spark, into the Apache Incubator.

The proposal is available online at, and it is appended
to this email.

We are looking for additional mentors to help with this project, and we
would much appreciate your guidance and advice.

Thank-you in advance,
David Fallside

= Spark-Kernel Proposal =

== Abstract ==
Spark-Kernel provides applications with a mechanism to interactively and
remotely access Apache Spark.

== Proposal ==
The Spark-Kernel enables interactive applications to access Apache Spark
clusters. More specifically:
 * Applications can send code-snippets and libraries for execution by Spark
 * Applications can be deployed separately from Spark clusters and
communicate with the Spark-Kernel using the provided Spark-Kernel client
 * Execution results and streaming data can be sent back to calling
 * Applications no longer have to be network connected to the workers on a
Spark cluster because the Spark-Kernel acts as each application’s proxy
 * Work has started on enabling Spark-Kernel to support languages in
addition to Scala, namely Python (with PySpark), R (with SparkR), and SQL
(with SparkSQL)

== Background & Rationale ==
Apache Spark provides applications with a fast and general purpose
distributed computing engine that supports static and streaming data,
tabular and graph representations of data, and an extensive library of
machine learning libraries. Consequently, a wide variety of applications
will be written for Spark and there will be interactive applications that
require relatively frequent function evaluations, and batch-oriented
applications that require one-shot or only occasional evaluation.

Apache Spark provides two mechanisms for applications to connect with
Spark. The primary mechanism launches applications on Spark clusters using
(; this
requires developers to bundle their application code plus any dependencies
into JAR files, and then submit them to Spark. A second mechanism is an
which enables applications to issue SQL queries against SparkSQL.

Our experience when developing interactive applications, such as analytic
applications and Jupyter Notebooks, to run against Spark was that the
spark-submit mechanism was overly cumbersome and slow (requiring JAR
creation and forking processes to run spark-submit), and the SQL interface
was too limiting and did not offer easy access to components other than
SparkSQL, such as streaming. The most promising mechanism provided by
Apache Spark was the command-line shell
which enabled us to execute code snippets and dynamically control the
tasks submitted to  a Spark cluster. Spark does not provide the
command-line shell as a consumable service but it provided us with the
starting point from which we developed the Spark-Kernel.

== Current Status ==
Spark-Kernel was first developed by a small team working on an
internal-IBM Spark-related project in July 2014. In recognition of its
likely general utility to Spark users and developers, in November 2014 the
Spark-Kernel project was moved to GitHub and made available under the
Apache License V2.

== Meritocracy ==
The current developers are familiar with the meritocratic open source
development process at Apache. As the project has gathered interest at
GitHub the developers have actively started a process to invite additional
developers into the project, and we have at least one new developer who is
ready to contribute code to the project.

== Community ==
We started building a community around the Spark-Kernel project when we
moved it to GitHub about one year ago. Since then we have grown to about
70 people, and there are regular requests and suggestions from the
community. We believe that providing Apache Spark application developers
with a general-purpose and interactive API holds a lot of community
potential, especially considering possible tie-in’s with the Jupyter and
data science community.

== Core Developers ==
The core developers of the project are currently all from IBM, from the
IBM Emerging Technology team and from IBM’s recently formed Spark
Technology Center.

== Alignment ==
Apache, as the home of Apache Spark, is the most natural home for the
Spark-Kernel project because it was designed to work with Apache Spark and
to provide capabilities for interactive applications and data science
tools not provided by Spark itself.

The Spark-Kernel also has an affinity with Jupyter ( because
it uses the Jupyter protocol for communications, and so Jupyter Notebooks
can directly use the Spark-Kernel as a kernel for communicating with
Apache Spark. However, we believe that the Spark-Kernel provides a
general-purpose mechanism enabling a wider variety of applications than
just Notebooks to access Spark, and so the Spark-Kernel’s greatest
affinity is with Apache and Apache Spark.

== Known Risks ==
=== Orphaned products ===
We believe the Spark-Kernel project has a low-risk of abandonment due to
interest in its continuing existence from several parties. More
specifically, the Spark-Kernel provides a capability that is not provided
by Apache Spark today but it enables a wider range of applications to
leverage Spark. For example, IBM uses (and is considering) the
Spark-Kernel in several offerings including its IBM Analytics for Apache
Spark product in the Bluemix Cloud. There are also a couple of other
commercial users who are using or considering its use in their offerings.
Furthermore, Jupyter Notebooks are used by data scientists and Spark is
gaining popularity as an analytic engine for them. Jupyter Notebooks are
very easily enabled with the Spark-Kernel and so there is another
constituency for it.

=== Inexperience with Open Source ===
The Spark-Kernel project has been running as an open-source project
(albeit with only IBM committers) for the past several months. The project
has an active issue tracker and due to the interest indicated by the
nature and volume of requests and comments, the team has publicly stated
it is beginning to build a process so they can accept third-party
contributions to the project.

=== Relationships with Other Apache Products ===
The Spark-Kernel has a clear affinity with the Apache Spark project
because it is designed to  provide capabilities for interactive
applications and data science tools not provided by Spark itself. The
Spark-Kernel can be a back-end for the Zeppelin project currently
incubating at Apache. There is interest from the Spark-Kernel community to
develop this capability and an experimental branch has been started.

=== Homogeneous Developers ===
The current group of developers working on Spark-Kernel are all from IBM
although the group is in the process of expanding its membership to
include members of the GitHub community who are not from IBM and who have
been active in the Spark-Kernel community in GutHub.

=== Reliance on Salaried Developers ===
The initial committers are full-time employees at IBM although not all
work on the project full-time.

=== Excessive Fascination with the Apache Brand ===
We believe the Spark-Kernel benefits Apache Spark application developers,
and we are interested in an Apache Spark-Kernel project to benefit these
developers by engaging a larger community, facilitating closer ties with
the existing Spark project, and yes, gaining more visibility for the
Spark-Kernel as a solution.

We have recently become aware that the project name “Spark-Kernel” may be
interpreted as having an association with an Apache project. If the
project is accepted by Apache, we suggest the project name remains the
same, but otherwise we will change it to one that does not imply any
Apache association.

=== Documentation ===
Comprehensive documentation including “Getting Started”, API
specifications and a Roadmap are available from the GitHub project, see

=== Initial Source ===
The source code resides at

=== External Dependencies ===
The Spark-Kernel depends upon a number of Apache projects:
 * Spark
 * Hadoop
 * Ivy
 * Commons

The Spark-Kernel also depends upon a number of other open source projects:
 * JeroMQ (LGPL with Static Linking Exception,
 * Akka (MIT)
 * JOpt Simple (MIT)
 * Spring Framework Core (Apache v2)
 * Play (Apache v2)
 * SLF4J (MIT)
 * Scala
 * Scalatest (Apache v2)
 * Scalactic (Apache v2)
 * Mockito (MIT)

== Required Resources ==
Developer and user mailing lists
 * (with moderated subscriptions)

A git repository:

A JIRA issue tracker:

== Initial Committers ==
The initial list of committers is:
 * Leugim Bustelo (
 * Jakob Odersky (
 * Luciano Resende (
 * Robert Senkbeil (
 * Corey Stubbs (
 * Miao Wang (
 * Sean Welleck (

=== Affiliations ===
All of the initial committers are employed by IBM.

== Sponsors ==
=== Champion ===
 * Sam Ruby (IBM)

=== Nominated Mentors ===
 * Luciano Resende

We wish to recruit additional mentors during incubation.

=== Sponsoring Entity ===
The Apache Incubator.

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