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Hadoop, mail # dev - Heads up - merge branch-trunk-win to trunk

Suresh Srinivas 2013-02-08, 01:42
Eli Collins 2013-02-08, 02:46
Suresh Srinivas 2013-02-08, 17:12
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RE: Heads up - merge branch-trunk-win to trunk
Mahadevan Venkatraman 2013-02-08, 02:41
It is super exciting to look at the prospect of these changes being merged to trunk. Having Windows as one of the supported Hadoop platforms is a fantastic opportunity both for the Hadoop project and Microsoft customers.

This work began around a year back when a few of us started with a basic port of Hadoop on Windows. Ever since, the Hadoop team in Microsoft have made significant progress in the following areas:
(PS: Some of these items are already included in Suresh's email, but including again for completeness)

- Command-line scripts for the Hadoop surface area
- Mapping the HDFS permissions model to Windows
- Abstracted and reconciled mismatches around differences in Path semantics in Java and Windows
- Native Task Controller for Windows
- Implementation of a Block Placement Policy to support cloud environments, more specifically Azure.
- Implementation of Hadoop native libraries for Windows (compression codecs, native I/O) - Several reliability issues, including race-conditions, intermittent test failures, resource leaks.
- Several new unit test cases written for the above changes

In the process, we have closely engaged with the Apache open source community and have got great support and assistance from the community in terms of contributing fixes, code review comments and commits.

In addition, the Hadoop team at Microsoft has also made good progress in other projects including Hive, Pig, Sqoop, Oozie, HCat and HBase. Many of these changes have already been committed to the respective trunks with help from various committers and contributors. It is great to see the commitment of the community to support multiple platforms, and we look forward to the day when a developer/customer is able to successfully deploy a complete solution stack based on Apache Hadoop releases.

Next Steps:

All of the above changes are part of the Windows Azure HDInsight and HDInsight Server products from Microsoft. We have successfully on-boarded several internal customers and have been running production workloads on Windows Azure HDInsight. Our vision is to create a big data platform based on Hadoop, and we are committed to helping make Hadoop a world-class solution that anyone can use to solve their biggest data challenges.

As an immediate next step, we would like to have a discussion around how we can ensure that the quality of the mainline Hadoop branches on Windows is maintained. To this end, we would like to get to the state where we have pre-checkin validation gates and nightly test runs enabled on Windows. If you have any suggestions around this, please do send an email.  We are committed to helping sustain the long-term quality of Hadoop on both Linux and Windows.

We sincerely thank the community for their contribution and support so far. And hope to continue having a close engagement in the future.

-Microsoft HDInsight Team
-----Original Message-----
From: Suresh Srinivas [mailto:[EMAIL PROTECTED]]
Sent: Thursday, February 7, 2013 5:42 PM
Subject: Heads up - merge branch-trunk-win to trunk

The support for Hadoop on Windows was proposed in HADOOP-8079<https://issues.apache.org/jira/browse/HADOOP-8079> almost a year ago. The goal was to make Hadoop natively integrated, full-featured, and performance and scalability tuned on Windows Server or Windows Azure.
We are happy to announce that a lot of progress has been made in this regard.

Initial work started in a feature branch, branch-1-win, based on branch-1.
The details related to the work done in the branch can be seen in CHANGES.txt<http://svn.apache.org/viewvc/hadoop/common/branches/branch-1-win/CHANGES.branch-1-win.txt?view=markup>.
This work has been ported to a branch, branch-trunk-win, based on trunk.
Merge patch for this is available on

Highlights of the work done so far:
1. Necessary changes in Hadoop to run natively on Windows. These changes handle differences in platforms related to path names, process/task management etc.
2. Addition of winutils tools for managing file permissions and ownership, user group mapping, hardlinks, symbolic links, chmod, disk utilization, and process/task management.
3. Added cmd scripts equivalent to existing shell scripts hadoop-daemon.sh, start and stop scripts.
4. Addition of block placement policy implemnation to support cloud enviroment, more specifically Azure.

We are very close to wrapping up the work in branch-trunk-win and getting ready for a merge. Currently the merge patch is passing close to 100% of unit tests on Linux. Soon I will call for a vote to merge this branch into trunk.

Next steps:
1. Call for vote to merge branch-trunk-win to trunk, when the work completes and precommit build is clean.
2. Start a discussion on adding Jenkins precommit builds on windows and how to integrate that with the existing commit process.

Let me know if you have any questions.