I mentioned this offline to others too.

We've had lots of discussions in the past about contrib projects overall in Hadoop and we moved away from there.

The same started happening with YARN, and we took a stand that YARN shouldn't run into the same umbrella issue. You can see the JIRA discussions on Paas On YARN etc for more context.

As for Weave, it represents a good programming model (threads) alongside MR and so deserves its own home IMO.


On Nov 3, 2013, at 11:21 PM, Roman Shaposhnik wrote:

Have you guys considered contributing this code directly to Hadoop?

From what you are describing it sounds like a developer friendly library
wrapped around YARN (along the lines of kitten:


On Tue, Oct 29, 2013 at 12:53 PM, Andreas Neumann <anew@apache.org> wrote:
I would like to propose Weave, an abstraction over Apache Hadoop® YARN to
reduce the complexity of developing distributed applications, as an
Apache Incubator

The proposal is included in plain text. I would also like to put this on
the wiki, but I appear to lack privileges to create pages. What do I need
to do to get permission?



Weave is an abstraction over Apache Hadoop® YARN that reduces the
complexity of developing distributed applications, allowing developers to
focus more on their business logic.


Weave is a set of libraries that reduces the complexity of developing
distributed applications. It exposes the distributed capabilities of Apache
Hadoop® YARN via a simple and intuitive programming model similar to Java
threads. Weave also has built-in capabilities required by many distributed
applications, such as real-time application logs and metrics collection,
application lifecycle management, and network service discovery.


Hadoop YARN is a generic cluster resource manager that supports any type of
distributed application. However, YARN’s interfaces are too low level for
rapid application development. It requires a great deal of boilerplate code
even for a simple application, creating a high ramp up cost that can turn
developers away.

Weave is designed to improve this situation with a programming model that
makes running distributed applications as easy as running Java threads.
With the abstraction provided by Weave, applications can be executed in
process threads during development and unit testing and then be deployed to
a YARN cluster without any modifications.

Weave also has built-in support for real-time application logs and metrics
collection, delegation token renewal, application lifecycle management, and
network service discovery. This greatly reduces the pain that developers
face when developing, debugging, deploying and monitoring distributed

Weave is not a replacement for YARN, it’s a framework that operates on top
of YARN.


Developers who write YARN applications typically find themselves
implementing the same (or similar) boilerplate code over and over again for
every application. It makes sense to distill this common code into a
reusable set of libraries that is perpetually maintained and improved by a
diverse community of developers.

Weave’s simple thread-like programming model will enable many Java
programmers to develop distributed applications. We believe that this
simplicity will attract developers who would otherwise be discouraged by
complexity, and many new use cases will emerge for the usage of YARN.

Incubating Weave as an Apache project makes sense because Weave is a
framework built on top of YARN, and Weave uses Apache Zookeeper, HDFS,
Kafka, and other Apache software (see the External Dependencies section).

Current Status

Weave was initially developed at Continuuity. The Weave codebase is
currently hosted in a public repository at github.com, which will seed the
Apache git repository.

Our intent with this incubator proposal is to start building a diverse
developer community around Weave following the Apache meritocracy model.
Since Weave was initially developed in early 2013, we have had fast
adoption and contributions within Continuuity. We are looking forward to
new contributors. We wish to build a community based on Apache's
meritocracy principles, working with those who contribute significantly to
the project and welcoming them to be committers both during the incubation
process and beyond.

Weave is currently being used internally at Continuuity and is at the core
of our products. We hope to extend our contributor base significantly and
we will invite all who are interested in simplifying the development of
distributed applications to participate.

Core Developers
Weave is currently being developed by five engineers at Continuuity:
Terence Yim, Andreas Neumann, Gary Helmling, Poorna Chandra and Albert
Terence Yim is an Apache committer for Helix, Andreas is an Apache
committer and PMC member for Oozie, and Gary Helmling is an Apache
committer and PMC member for HBase. Poorna Chandra and Albert Shau have
made many contributions to Weave.

The ASF is the natural choice to host the Weave project as its goal of
encouraging community-driven open source projects fits with our vision for

Additionally, many other projects with which we are familiar and expect
Weave to integrate with, such as ZooKeeper, YARN, HDFS, log4j, and others
mentioned in the External Dependencies section are Apache projects, and
Weave will benefit by close proximity to them.

Known Risks

Orphaned Products
There is very little risk of Weave being orphaned, as it is a key part of
Continuuity’s products. The core Weave developers plan to continue to work
on Weave, and Continuuity has funding in place to support their efforts
going forward.
Many other Big Data companies can benefit from Weave, and we have already
received interest from various entities that would like to use and
contribute to Weave.

Inexperience with Open Source
Several of the core developers have experience with open source
development. Terence Yim, Andreas Neumann and Gary Helmling are currently
Apache committers for Helix, Oozie and HBase respectively
Homogeneous Developers

The current core developers are all Continuuity employees. However, we
intend to establish a developer community that includes independent and
corporate contributors. We are encouraging new contributors via our mailing
lists, public presentations, and personal contacts, and we will continue to
do so. Various entities have already expressed interest in becoming
involved with Weave.

Reliance on Salaried Developers
Currently, these developers are paid to work on Weave. Once the project has
built a community, we expect to attract committers, developers and
community other the current core developers. However, because Continuuity
products use Weave internally, the reliance on salaried developers is
unlikely to change, at least in the near term.

Relationships with Other Apache Products
Weave is deeply integrated with Apache projects. Weave uses Apache YARN as
its underlying resource management and task scheduling system and Apache
Zookeeper for coordination. In addition, Weave uses Apache HDFS and Apache
Kafka. A number of other Apache projects are Weave dependencies and are
listed in the External Dependencies section.

An Excessive Fascination with the Apache Brand
While we respect the reputation of the Apache brand and have no doubt that
it will attract contributors and users, our interest is primarily to give
Weave a solid home as an open source project following an established
development model. We have also given additional reasons in the Rationale
and Alignment sections.



Initial Source

The Weave codebase is currently hosted at

External Dependencies

The dependencies all have Apache-compatible licenses:
• avro (Apache 2.0)
• hadoop (Apache 2.0)
• gson (Apache 2.0)
• guava-libraries (Apache 2.0)
• hbase (Apache 2.0)
• hdfs (Apache 2.0)
• kafka (Apache 2.0)
• netty (Apache 2.0)
• snappy-java (Apache 2.0)
• yarn (Apache 2.0)
• zookeeper (Apache 2.0)
• asm (BSD)
• junit (EPL v1.0)
• logback (EPL v1.0 )
• slf4j (MIT)


Weave will depend on secure Hadoop, which can optionally use Kerberos.

Required Resources

Mailing Lists
- weave-private for private PMC discussions (with moderated subscriptions)
- weave-dev for technical discussions among contributors
- weave-commits for notification about commits

Subversion Directory
Git is the preferred source control system: git://git.apache.org/weave

Issue Tracking

Other Resources
The existing code already has unit tests, so we would like a Hudson
instance to run them whenever a new patch is submitted. This can be added
after project creation.

Initial Committers

• Terence Yim
• Andreas Neumann
• Gary Helmling
• Poorna Chandra
• Albert Shau


• Terence Yim (Continuuity)
• Andreas Neumann (Continuuity)
• Gary Helmling (Continuuity)
• Poorna Chandra (Continuuity)
• Albert Shau (Continuuity)


Vinod K <vinodkv at apache dot org> (Apache Member)

Nominated Mentors
• Arun C Murthy <acmurthy at apache dot org>
• Tom White <tomwhite at apache dot org>
• Patrick Hunt <phunt at apache dot org>

Sponsoring Entity
We are requesting that the Incubator sponsor this project.

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