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From Tommaso Teofili <>
Subject Re: [VOTE] Accept Howl as an Incubator Project
Date Wed, 23 Feb 2011 08:16:19 GMT

2011/2/23 Alan Gates <>

> I would like to call a vote on accepting Howl as an Incubator project.  The
> proposal is available at
>  You can see the discussion from the proposal thread at
> Alan.
> ----------------------
> Abstract
> Howl is a table and storage management service for data created using
> Apache Hadoop.
> Proposal
> The vision of Howl is to provide table management and storage management
> layers for Apache Hadoop. This includes:
>        • Providing a shared schema and data type mechanism.
>        • Providing a table abstraction so that users need not be concerned
> with where or how their data is stored.
>        • Providing interoperability across data processing tools such as
> Pig, Map Reduce, Streaming, and Hive.
> Background
> Data processors using Apache Hadoop have a common need for table management
> services. The goal of a table management service is to track data that
> exists in a Hadoop grid and present that data to users in a tabular format.
> Such a table management service needs to provide a single input and output
> format to users so that individual users need not be concerned with the
> storage formats that are chosen for particular data sets. As part of having
> a single format, the data will need to be described by one type of schema
> and have a single datatype system.
> Additionally, users should be free to choose the best tools for their use
> cases. The Hadoop project includes Map Reduce, Streaming, Pig, and Hive, and
> additional tools exist such as Cascading. Each of these tools has users who
> prefer it, and there are use cases best addressed by each of these tools.
> Two users on the same grid who need to share data should not be constrained
> to use the same tool but rather should be free to choose the best tool for
> their use case. A table management service that presents data in the same
> way to all of the tools can alleviate this problem by providing interfaces
> to each of the data processing tools.
> There are also a few other features a table management service should
> provide, such as notification of when data arrives.
> A couple of developers at Yahoo! started the project. It is based on the
> Hive MetaStore component. There is good amount of interest in such a service
> expressed from Yahoo!, Facebook, LinkedIn, and, others. We are therefore
> proposing to place Howl in the Apache incubator and to build an open source
> community around it.
> Rationale
> There is a strong need for a table management service, especially for large
> grids with petabytes of data, and where the data volume is increasing by the
> day. Hadoop users need to find data to read and have a place to store  their
> data. Currently users must understand the location of data to read, the
> storage format, compression techniques used, etc. To write data they need to
> understand where on HDFS their data belongs, the best compression format to
> use, how their data should be serialized, etc.
> Most users do not want to be concerned with these issues. They want these
> managed for them.
> Having it as an Apache Open Source project will highly benefit Howl from
> the point of view of getting a large community that currently uses Hadoop
> and the other products built around Hadoop (like Pig, Hive, etc.). Users of
> the Hadoop ecosystem can influence Howl’s roadmap, and contribute to it.
> Looking at it in another way, we believe having Howl as part of the Hadoop
> ecosystem will be a great benefit to the current Hadoop/Pig/Hive community
> too.
> Current Status
> Meritocracy
> Our intent with this incubator proposal is to start building a diverse
> developer community around Howl following the Apache meritocracy model. We
> have wanted to make the project open source and encourage contributors from
> multiple organizations from the start. We plan to provide plenty of support
> to new developers and to quickly recruit those who make solid contributions
> to committer status.
> Community
> Howl is currently being used by developers at Yahoo! and there has been an
> expressed interest from LinkedIn and Facebook. Yahoo! also plans to deploy
> the current version of Howl in production soon. We hope to extend the user
> and developer base further in the future. The current developers and users
> are all interested in building a solid open source community around Howl.
> To work towards an open source community, we have started using the GitHub
> issue tracker and mailing lists at Yahoo! for development discussions within
> our group.
> Core Developers
> Howl is currently being developed by four engineers from Yahoo! - Devaraj
> Das, Ashutosh Chauhan, Sushanth Sowmyan, and Mac Yang. All the engineers
> have deep expertise in Hadoop and the Hadoop Ecosystem in general.
> Alignment
> The ASF is a natural host for Howl given that it is already the home of
> Hadoop, Pig, HBase, Cassandra, and other emerging cloud software projects.
> Howl was designed to support Hadoop from the beginning in order to solve
> data management challenges in Hadoop clusters. Howl complements the existing
> Apache cloud computing projects by providing a unified way to manage data.
> Known Risks
> Orphaned Products
> The core developers plan to work full time on the project. There is very
> little risk of Howl getting orphaned since large companies like Yahoo! are
> planning to deploy this in their production Hadoop clusters. We believe we
> can build an active developer community around Howl (companies like Facebook
> and LinkedIn have also expressed interest).
> Inexperience with Open Source
> All of the core developers are active users and followers of open source.
> Devaraj Das is an Apache Hadoop committer and Apache Hadoop PMC member, and
> has experience with the Apache infrastructure and development process.
> Ashutosh Chauhan is an Apache Pig committer and Apache Pig PMC member.
> Sushanth Sowmyan and Mac Yang made contributions to the Apache Hive and the
> Apache Chukwa projects.
> Homogeneous Developers
> The current core developers are all from Yahoo! However, we hope to
> establish a developer community that includes contributors from several
> corporations, and we are starting to work towards this with Facebook and
> LinkedIn.
> Reliance on Salaried Developers
> Currently, the developers are paid to do work on Howl. However, once the
> project has a community built around it, we expect to get committers and
> developers from outside the current core developers. Companies like Yahoo!
> are invested in Howl being a solution to the data management problem in
> Hadoop clusters, and that is not likely to change.
> Relationships with Other Apache Products
> Howl is going to be used by users of Hadoop, Pig, and Hive. See section
> Initial Source below for more information about Howl's relationship to Hive.
> An Excessive Fascination with the Apache Brand
> While we respect the reputation of the Apache brand and have no doubts that
> it will attract contributors and users, our interest is primarily to give
> Howl a solid home as an open source project following an established
> development model. We have also given reasons in the Rationale and Alignment
> sections.
> Documentation
> Information about Howl can be found at
> The following sources may be useful to start with:
>        •
> The GitHub site:
>        •
> The roadmap:
> Initial Source
> Howl has been under development since Summer 2010 by a team of engineers in
> Yahoo!. It is currently hosted on GitHub under an Apache license at
> The initial development of Howl has consisted of:
>        • maintaining a branch of the entire Hive codebase
>        • getting Howl-related patches committed to Hive
>        • developing Howl-specific plugins and wrappers to customize Hive
> behavior
> At runtime, Howl executes Hive code for metastore and CLI+DDL, disabling
> anything related to Hadoop map/reduce execution. It also makes use of the
> RCFile storage format contained in Hive.
> This approach was taken as a first step in order to validate the required
> functionality and get a production version working. However, in the
> long-term, maintaining a clone of Hive is undesirable. One possible
> resolution is to factor the metastore+CLI+DDL components out of Hive and
> move them into Howl (making Hive dependent on Howl). Another possible
> resolution is to remove the copy of Hive from Howl and do the build/release
> engineering necessary to make Howl depend on Hive. As part of the incubation
> process, we plan to work towards resolution of  these issues.
> External Dependencies
> The dependencies all have Apache compatible licenses.
> Cryptography
> Not applicable.
> Required Resources
> Mailing Lists
>        • howl-private for private PMC discussions (with moderated
> subscriptions)
>        • howl-dev
>        • howl-commits
>        • howl-user
> Subversion Directory
> Issue Tracking
> JIRA Howl (HOWL)
> 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
>        • Devaraj Das
>        • Ashutosh Chauhan
>        • Sushanth Sowmyan
>        • Mac Yang
>        • Paul Yang
>        • Alan Gates
> A CLA is already on file for Sushanth.
> Affiliations
>        • Devaraj Das (Yahoo!)
>        • Ashutosh Chauhan (Yahoo!)
>        • Sushanth Sowmyan (Yahoo!)
>        • Mac Yang (Yahoo!)
>        • Paul Yang (Facebook)
>        • Alan Gates (Yahoo!)
> Sponsors
> Champion
> Owen O’Malley
> Nominated Mentors
>        • Olga Natkovich (Pig PMC member and Apache VP for Pig)
>        • Alan Gates (Pig PMC member)
>        • John Sichi (Hive PMC member)
> Sponsoring Entity
> We are requesting the Incubator to sponsor this project.
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