How To Release Mahout

This page is prepared for Mahout committers. You need committer rights to create a new Mahout release.

Release Planning

Start a discussion on mahout-dev about having a release, questions to bring up include:

Code Freeze

For 7-14 days prior to the release target date, have a “code freeze” where committers agree to only commit things if they:

  • Are documentation improvements (including fixes to eliminate Javadoc warnings)
  • Are new test cases that improve test coverage
  • Are bug fixes found because of improved test coverage
  • Are new tests and bug fixes for new bugs encountered by manually testing

Steps For Release Engineer

Before building release

  1. Check that all tests pass after a clean compile: mvn clean test
  2. Check that there are no remaining unresolved Jira issues with the upcoming version number listed as the “Fix” version
  3. Publish any prev. unpublished Third Party Deps: Thirdparty Dependencies

Previewing the Artifacts

  1. To build the artifacts:
  2. mvn -Pmahout-release,apache-release,hadoop2 package

Making a release

  • Check if documentation needs an update
  • Update the web site’s news by updating a working copy of the SVN directory at
  • Commit these changes. It is important to do this prior to the build so that it is reflected in the copy of the website included with the release for documentation purposes.
  • If this is your first release, add your key to the KEYS file. The KEYS file is located on Github at and copy it to the release directory. Make sure you commit your change. See
  • Ensure you have set up standard Apache committer settings in ~/.m2/settings.xml as per this page .
  • Add a profile to your ~/.m2/settings.xml in the section with:
mahout_release YOUR PGP KEY NAME YOUR SIGNING PASSCODE HERE mahout.releases::default:: USERNAME
  • You may also need to add the following to the section in ~/.m2/settings.xml in order to upload artifacts (as the -Dusername= -Dpassword= didn't work for Grant for 0.8, but this did):
apache.releases.https USERNAME PASSWORD
  • Set environment variable MAVEN_OPTS to -Xmx1024m to ensure the tests can run
  • export _JAVA_OPTIONS=”-Xmx1g”
  • If you are outside the US, then may not resolve to the main US-based Subversion servers. (Compare the IP address you get for with to see if they are different.) This will cause problems during the release since it will create a revision and then immediately access, but, there is a replication lag of perhaps a minute to the non-US servers. To temporarily force using the US-based server, edit your equivalent of /etc/hosts and map the IP address of to
  • Create the release candidate:

    mvn -Pmahout-release,apache-release,hadoop2 release:prepare release:perform

    If you have problems authenticating to, try adding to the command line

    -Dusername=\[user]\ -Dpassword=\[password\]

If it screws up, first try doing:

mvn -Dmahout-release,apache-release,hadoop2 release:rollback.

followed by

mvn -Dmahout-release,apache-release,hadoop2 release:clean

This will likely save you time and do the right thing.

You may also have to rollback the version numbers in the POM files.

If you want to skip test cases while rebuilding, use

mvn -DpreparationGoals=”clean compile” release:prepare release:perform

  • Review the artifacts, etc. on the Apache Repository (using Sonatype’s Nexus application) site: You will need to login using your ASF SVN credentials and then browse to the staging area.
  • Once you have reviewed the artifacts, you will need to “Close” out the staging area under Nexus, which then makes the artifacts available for others to see.
    • Log in to Nexus
    • Click the Staging Repositories link in the left hand menu
    • Click the Mahout staged one that was just uploaded by the release:perform target
    • Click Close in the toolbar. See for a picture
    • Copy the “Repository URL” link to your email; it should be like
  • Call a VOTE on Votes require 3 days before passing. See Apache [release policy|] for more info.
  • If there’s a problem, you need to unwind the release and start all over. <blockquote> mvn -Pmahout-release,apache-release,hadoop2 versions:set -DnewVersion=PREVIOUS_SNAPSHOT

      mvn -Pmahout-release,apache-release,hadoop2 versions:commit
      git commit 
      git push --delete apache <tagname> (deletes the remote tag)
      git tag -d tagname (deletes the local tag)
  • Release the artifact in the Nexus Repository in the same way you Closed it earlier.
  • Add your key to the KEYS file at
  • Copy the assemblies and their supporting files (tar.gz, zip, tar.bz2, plus .asc, .md5, .pom, .sha1 files) to the ASF mirrors at: You should make sure the group "mahout" owns the files and that they are read only (-r--r--r-- in UNIX-speak). See [Guide To Distributing Existing Releases Through The ASF Mirrors|] and the links that are there.
    • cd /www/
    • mkdir
    • cd
    • wget -e robots=off –no-check-certificate -np -r
    • mv* .
    • rm -rf
    • rm index.html
  • Wait 24 hours for release to propagate to mirrors.
  • Clean up JIRA: Bulk close all X.Y JIRA issues. Mark the Version number as being released (see Manage Versions.) Add the next version (X.Y+1) if necessary.
  • Update release version on and *
  • Send announcements to the user and developer lists.

See also:

  • *

Post Release


  • Create the next version in JIRA (if it doesn’t already exist)
  • Mark the version as “released” in JIRA (noting the release date)


  • Change wiki to match current best practices (remove/change deprecations, etc)


  • update freshmeat
  • blog away
  • Update MLOSS entry: See Grant for details.

TODO: Things To Cleanup in this document

  • more specifics about things to test before starting or after packaging (RAT, run scripts against example, etc…)
  • include info about [Voting]