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As you go through the steps in this guide to perform a release, if you find anything out of date, please update it so that it is accurate for the next release.

Placeholder Values in this Document

This guide is written to be generic for any release. As such, where string literals, code snippets, or parameter/argument values are used, placeholders will be used for values that are specific for each release.

PlaceholderDescriptionExample Value
${BRANCH}The branch from which the release will be mademaster
${VERSION}The version being released (typically based off dropping the "-SNAPSHOT" suffix for the current development branch that is being released to mark a stable version0.3.0

The next development version that will being after the release is completed. Typically the next minor version with the "-SNAPSHOT" suffix.

${JIRA_TICKET}The ticket for the Release Manger's activities (e.g., labeling release commits, etc.)NIFIREG-176
${JIRA_VERSION_URL}The link to the version in Jira that corresponds to this release and contains all the tickets
${JIRA_RELEASE_NOTES_URL}The link to the JIRA auto-generated release notes based on the Jira version
${RC}The number of the release candidate, an incrementing integer starting at 11
${RC_TAG_COMMIT_ID}The 40 byte commit ID of the RC tag created during the Maven release process2fef9fac2b627ee1f3428b07019b333c68f65f2d
${STAGING_REPO_ID}The temporary Apache Nexus repository ID where staged artifacts have been placedorgapachenifi-1132


The release manager's apache user idkdoran
${RELEASE_TAG}The git tag that will added to mark the final releaserel/nifi-registry-0.3.0
${VOTE_THREAD_URL}The URL for the Apache Pony Mail archive of the release vote thread

Prepare and Stage the Release

  1. Ensure you have completed all the steps in the following sections below:
    1. Appendix A: First Time Release Manager Prep
    2. Appendix B: Configure GPG, Maven, and Git for Signing and Deploying

  2. Create a Jira ticket for the release tasks for this release version. The resulting Jira ticket number is referred to as ${JIRA_TICKET} in this guide. Example:
    NIFIREG-87 - Getting issue details... STATUS

  3. If it does not already exist, create the ${VERSION} in Jira from the NiFi Registry Versions management page (requires PMC group access).

  4. Create meaningful release notes for this version if not already created. A good starting point is reviewing the Jira generated release notes from the NiFi Registry Versions management page or this JQL filter: project = NIFIREG and fixVersion = ${VERSION}
    Enter the release notes at the top of the Release Notes page of the NiFi Registry wiki:
    It will be necessary to use a placeholder for the release date, which will be updated once the release is finalized.

  5. Create a new branch off ${BRANCH} (typically master) named after the Jira ticket.

    git checkout -b ${JIRA_TICKET}-RC${RC} ${BRANCH}
  6. Verify that Maven has sufficient heap space to perform the build tasks. Some plugins and parts of the build consume a surprisingly large amount of space. These settings have been shown to work for Java 8 for NiFi Registry version 0.2.0 and later:

    export MAVEN_OPTS="-Xms1024m -Xmx3076m"
  7. Ensure the full application builds and all tests work by executing a full build with tests. The Maven command we use for a full build is in the .travis.yml file at the root of the git repository. At the time of this writing, it is:

    mvn clean install -Pcontrib-check,integration-tests,jsUnitTests
  8. Start and test the application from the root source folder. NiFi Registry should be up and running at http://localhost:18080/nifi-registry

    cd nifi-registry-assembly/target/nifi-registry-${VERSION}-bin/nifi-registry-${VERSION}
    ./bin/ start
  9. Start and test NiFi pointing to the NiFi Registry by performing basic flow versioning operations.

  10. Evaluate and ensure the appropriate license headers are present on all source files.

  11. Ensure LICENSE and NOTICE files are complete and accurate for both the source and the assembly. (Developers should always be keeping these up to date as they go along adding source and modifying dependencies to keep this burden manageable.)

Perform the Release

  1. Ensure you have completed all the steps in the section below: Appendix B: Configure GPG, Maven, and Git for Signing and Deploying. Otherwise, the Maven release plugin may fail at the signing or deploying stage.

  2. Use the Maven Release Plugin to prepare the release with this command:

    mvn --batch-mode release:prepare \
      -Psigned_release \
      -DscmCommentPrefix="${JIRA_TICKET}-RC${RC} " \
      -Dtag="nifi-registry-${VERSION}-RC${RC}" \
      -DreleaseVersion="${VERSION}" \
      -DdevelopmentVersion="${NEXT_VERSION}" \
  3. Review the release preparation results. 
    If problems are found, mvn release:rollback will revert the changes, or it may also be necessary to run mvn release:clean to get the project to a state where it can be rebuilt.

  4. If the release preparation completed without problems, perform the release and deploy artifacts to staging:

    mvn release:perform \
      -Psigned_release \
      -DscmCommentPrefix="${JIRA_TICKET}-RC${RC} " \

    When this completes the artifacts have been released to the Apache Nexus staging repository at
    A local release branch has been created and there should the staging repository ID returned in a log entry like this:

    [INFO] * Closing staging repository with ID "orgapachenifi-1088"

    This staging repository ID is referred to by ${STAGING_REPO_ID}  in this release guide.

  5. Browse to the Apache Staging Repository ( and login with your Apache committer credentials. You should see the newly created staging repository listed. If you click on that you can inspect the various staged artifacts.

  6. Validate that all the various aspects of the staged artifacts appear correct

    1. Download the sources. Do they compile cleanly? If the result is a build does it execute?

    2. Validate the hashes match.
    3. Validate that the sources contain no unexpected binaries.
    4. Validate the signature for the build and hashes.
    5. Validate the LICENSE/NOTICE/Headers.
    6. Validate that the README is present and provides sufficient information to build and if necessary execute.

  7. If the validated artifacts all look good then push the local git branch to the ASF repository.

    git push asf ${JIRA_TICKET}-RC${RC}

    From this branch, the ${RC_TAG_COMMIT_ID} will be the 40 byte commit hash with the comment:
    ${JIRA_TICKET}-RC${RC} prepare release nifi-registry-${VERSION}-RC${RC}

  8. Create the signature and hashes for the source release and convenience binary files.

    - ASCII armored GPG signatures (--digest-algo=SHA512 selects the SHA512 hash algorithm). Or you can configure GPG to always prefer stronger hashes.
    - Generate SHA256 hash summaries.
    - Generate SHA512 hash summaries.

    # For the source release artifact downloaded from the staging repository, i.e. nifi-registry-${VERSION}
    gpg -a -b --digest-algo=SHA512 nifi-registry-${VERSION}
    shasum -a 256 nifi-registry-${VERSION} | cut -d" " -f1 >  nifi-registry-${VERSION}
    shasum -a 512 nifi-registry-${VERSION} | cut -d" " -f1 >  nifi-registry-${VERSION}
    # For the convenience binary nifi-registry-${VERSION}, generated by building the downloaded source in the previous step
    gpg -a -b --digest-algo=SHA512 nifi-registry-${VERSION}
    shasum -a 256 nifi-registry-${VERSION} | cut -d" " -f1 >  nifi-registry-${VERSION}
    shasum -a 512 nifi-registry-${VERSION} | cut -d" " -f1 >  nifi-registry-${VERSION}
    # For the convenience binary nifi-registry-${VERSION}-bin.tar.gz, generated by building the downloaded source in the previous step
    gpg -a -b --digest-algo=SHA512 nifi-registry-${VERSION}-bin.tar.gz
    shasum -a 256 nifi-registry-${VERSION}-bin.tar.gz | cut -d" " -f1 >  nifi-registry-${VERSION}-bin.tar.gz.sha256
    shasum -a 512 nifi-registry-${VERSION}-bin.tar.gz | cut -d" " -f1 >  nifi-registry-${VERSION}-bin.tar.gz.sha512
  9. For reviewing of the release candidate, commit the source release and convenience binaries files along with their hashes and signatures to${VERSION}.

    svn checkout dist-dev-nifi
    cd dist-dev-nifi/nifi-registry
    mkdir nifi-registry-${VERSION}
    # Add source release and binaries to nifi-registry-${VERSION}, along with their corresponding signature and hash files
    svn update 
    svn add nifi-registry-${VERSION}
    svn commit -m "${JIRA_TICKET} Staging artifacts for nifi-registry-${VERSION}-RC${RC}" nifi-registry-${VERSION}

Error Recovery

If anything isn't correct about the staged artifacts you can drop the staged repo from and delete the local tag in git. If you also delete the local branch and clear your local maven repository under org/apache/nifi then it is as if the release never happened. Try to figure out what went wrong so this Release Guide can be updated or corrected if necessary.

So, as has been described here, you can test the release process until you get it right. The mvn versions:set and mvn versions:commit commands can come in handy to help do this so you can set versions to something clearly release test related.

The Release Vote

After the release source and artifacts are staged in the repositories, the RM sends a release vote to the community.

Once the release vote is called for, members of the developer community have 72 hours to evaluate the RC and cast their vote by replying to the "[VOTE] Release ..." email sent by the RM.

NOTE: The release vote is majority rule vote that must include at least 3 binding +1 votes Apache NiFi PMC members and more positive than negative binding votes.

  1. RM sends a vote request email to the NiFi Developers Mailing List.

    SUBJECT: [VOTE] Release Apache NiFi Registry ${VERSION}

     Template for the email body. Click here to expand...
    I am pleased to call this vote for the source release of Apache NiFi Registry ${VERSION}.
    The source zip, including signatures, digests, etc. can be found at:${VERSION}/
    The Git tag is nifi-registry-${VERSION}-RC${RC}
    The Git commit ID is ${RC_TAG_COMMIT_ID};a=commit;h=${RC_TAG_COMMIT_ID}
    Checksums of nifi-registry-${VERSION}
    SHA256: <64-CHAR-SHA256SUM-HASH>
    SHA512: <128-CHAR-SHA512SUM-HASH>
    Release artifacts are signed with the following key:${RM_USERID}.asc
    KEYS file available here:
    ${NN} issues were closed/resolved for this release:
    Release note highlights can be found here:
    The vote will be open for 72 hours.
    Please download the release candidate and evaluate the necessary items including checking hashes, signatures, build
    from source, and test. Then please vote:
    [ ] +1 Release this package as nifi-registry-${VERSION}
    [ ] +0 no opinion
    [ ] -1 Do not release this package because...
  2. RM sends the following helper email to the NiFi Developers Mailing List.
    SUBJECT: Apache NiFi Registry ${VERSION} RC${RC} Release Helper Guide

     Template for the email body. Click here to expand...
    Hello Apache NiFi community,
    Please find the associated guidance to help those interested in
    validating/verifying the Apache NiFi Registry release so they can vote.
    # Download latest KEYS file:
    # Import keys file:
    gpg --import KEYS
    # [optional] Clear out local maven artifact repository
    # Pull down nifi-registry-${VERSION} source release artifacts for review:
    # Verify the signature
    gpg --verify nifi-registry-${VERSION}
    # Verify the hashes (sha256, sha512) match the source and what was provided in the vote email thread
    shasum -a 1 nifi-registry-${VERSION}
    shasum -a 256 nifi-registry-${VERSION}
    shasum -a 512 nifi-registry-${VERSION}
    # Unzip nifi-registry-${VERSION}
    # Verify the build works including release audit tool (RAT) checks
    cd nifi-registry-${VERSION}
    mvn clean install -Pcontrib-check
    # Verify the contents contain a good README, NOTICE, and LICENSE.
    # Verify the git commit ID is correct
    # Verify the RC was branched off the correct git commit ID
    # Look at the resulting convenience binary as found in nifi-registry-assembly/target
    # Make sure the README, NOTICE, and LICENSE are present and correct
    # Run the resulting convenience binary and make sure it works as expected
    # Test integration between the Registry and NiFi
    Start the registry
        ./bin/ start
    Create a bucket in the registry
    - Go to the registry UI at http://localhost:18080/nifi-registry
    - Click the tool icon in the top right corner
    - Click New Bucket from the bucket table
    - Enter a name and click create
    Start NiFi
    Tell NiFi about your local registry instance
    - Go the controller settings for NiFi from the top-right menu
    - Select the Registry Clients tab
    - Add a new Registry Client giving it a name and the url of http://localhost:18080
    Create a process group and place it under version control
    - Right click on the PG and select the Version menu
    - Select Start Version Control
    - Choose the registry instance and bucket you want to use
    - Enter a name, description, and comment
    Go back to the registry and refresh the main page and you should see the versioned flow you just saved
    Import a new PG from a versioned flow
    - Drag on a new PG like normal
    - Instead of entering a name, click the Import link
    - Now choose the flow you saved before
    You should have a second identical PG now.
    # Send a response to the vote thread indicating a +1, 0, -1 based on your findings.
    Thank you for your time and effort to validate the release!
  3. Developers in the community review the release candidate and reply to the vote email with their vote.

  4. After 72 hours if at least 3 binding (PMC members) cast +1 votes, and the positive binding votes out number any negative binding votes then the vote passes and the release candidate is officially released. If the vote does not pass, corrections are made on the release branch and a new release candidate is put forward for a new vote.

  5. RM sends vote result email.
    FROM: ${RM_USER} 
    SUBJECT: [RESULT][VOTE] Release Apache NiFi Registry ${VERSION}

     Template for email body. Click here to expand...
    Apache NiFi Community,
    I am pleased to announce that the nifi-registry-${VERSION} release of Apache NiFi Registry passes with
        X +1 (binding) votes
        Y +1 (non-binding) votes
        0 0 votes
        0 -1 votes
    Thanks to all who helped make this release possible.
    Here is the vote thread: 

Finalize the Release

After the vote is complete and the release is approved, these steps complete the release process.

  1. Move convenience binaries and related artifacts from dist/dev to dist/release (note, the release branch requires PMC access):

    svn move -m "${JIRA_TICKET}"${VERSION}${VERSION}
  2. At, login with your Apache ID credentials, go to Staging Repositories, select Release and follow the instructions on the site.

  3. For the source code git repository, merge the release branch into master:

    git checkout master
    git merge --no-ff ${JIRA_TICKET}-RC${RC}
    git push asf master
  4. Update the Migration Guidance on the Wiki:

  5. Update the wiki release notes with the final date of the release:

  6. Update the NiFi website to point to the new download(s).
    - Remove older release artifacts from download page (leave the current release and the previous one). 
    - For the release just previous to this new one change the links to point to the archive location. See current page as an example of the needed URL changes. 
    - In addition to updating the download page as described delete artifacts other than the current/new release from the dist/nifi SVN storage. They are already in the archive location so no need to do anything else.

  7. If the release is on the latest development line, update the NiFi website documentation pages for NiFi Registry to match the release.
    - Run the NiFi Registry ${VERSION}
    - Pull down the documentation by running wget -prk http://${host}:${port}/nifi-registry-docs/documentation
    - Rename the file index file that was generated by running mv ${host}:${port}/nifi-registry-docs/documentation ${host}:${port}/nifi-registry-docs/index.html
    - Use svn to replace the nifi and nifi-docs folders in with those in the ${host}:${port} directory pulled down above

  8. In Jira, mark the ${JIRA_TICKET} resolved. All tickets for the Jira release version should now be resolved or closed. 
    Mark the release version for ${VERSION} as 'Released' using the NiFi Registry Versions management page. 
    This may also be a good time to create a Jira version for the next planned release of ${NEXT_VERSION} (usually the next minor version).

  9. Ensure the release artifacts are successfully mirrored to the archive, specifically${VERSION}/nifi-registry-${VERSION}-bin.tar.gz.
    If there were any issues with the above listed file not being available, it may be necessary to reach out to the ASF Infra team.

    Docker Image Note

    When the Docker image build is automated (as of this writing, not currently setup for NiFi Registry), then it is triggered by pushing the signed tag in the next step. The release artifacts must be present in the archive before continuing.
  10. Create a proper signed tag of the released codebase based on the RC tag created during the Maven release process.
    For instructions on setting up to sign your tag see: or the Appendix B section below.

    # create the tag in your local repo
    git tag -s rel/nifi-registry-${VERSION} -m "${JIRA_TICKET} signed release tag for approved release of NiFi Registry ${VERSION}" ${RC_TAG_COMMIT_ID}
    # push the tag to the ASF repo
    git push asf rel/nifi-registry-${VERSION}
  11. Build the new Docker image based on the artifacts accessible via the mirror. Tag the image as the current version and latest and push to the official repository. (TODO, expand these instructions for doing this manually or setup automation with ASF Infra as we have to NiFi.)

  12. Update Docker version information for the dockerhub image to point to the next release. For instance, if the ${NEXT_VERSION} is 0.4.0-SNAPSHOT, these values should be updated to 0.4.0, so that at the time of the next release they will reference the correct version number. This currently consists of two files:

    nifi-registry-core/nifi-registry-docker/dockerhub/Dockerfile, Line 24, and
    nifi-registry-core/nifi-registry-docker/dockerhub/DockerImage.txt, Line 16.

  13. After the release has been complete for 24 hours send the release announcement email.

    For an understanding of why you need to wait 24 hours, see:

    FROM: ${RM_USER}
    SUBJECT: [ANNOUNCE] Apache NiFi Registry ${VERSION} Release


     Template for email body. Click here to expand...
    The Apache NiFi team would like to announce the release of Apache NiFi Registry ${VERSION}.
    Apache NiFi is an easy to use, powerful, and reliable system to process and distribute data. Apache NiFi was made for dataflow. It supports highly configurable directed graphs of data routing, transformation, and system mediation logic.
    Registry, a subproject of Apache NiFi, is a complementary application that provides a central location for storage and management of shared resources across one or more instances of NiFi or MiNiFi.
    More details on Apache NiFi Registry, along with release artifacts, can be found here:
    Maven artifacts have been made available here:
    Issues closed/resolved for this list can be found here:
    Release note highlights can be found here:${VERSION}
    Thank you,
    The Apache NiFi team

Appendix A: First Time Release Manager Prep

These steps only have to be done once for any NiFi project release (NiFi, NiFi Registry, NiFi MiNiFi, etc.).

  1. Make sure you can login (using your Apache ID LDAP credentials) the Apache Nexus Server at: 

  2. Make sure you have write access to the Apache NiFi Wiki (for publishing release notes):

  3. Make sure your public PGP key has been added to:

  4. If you have never signed a release before, recommended to read

    1. If you don't have a code signing key already, follow the instructions there to generate and publish a new key pair.

    2. Once you have a key, add the public key to the dev KEYS file in the SVN repository. 
      If you use SVN infrequently, you may find this a useful reference for the command syntax:

      # Checkout the SVN repo:
      svn checkout dist-dev-nifi
      cd dist-dev-nifi
      # Follow the instructions at the top of the KEYS file to append your public code signing key
      gpg --list-sigs --fingerprint ${NAME_OR_KEYID} >> KEYS
      gpg --armor --export ${NAME_OR_KEYID} >> KEYS
      # Verify your key information has been appended correctly to the KEYS file
      # Commit the file back to the SVN repo
      svn commit KEYS -m "Adding code signing key to KEYS file"
      # Prior to the release, move the KEYS file to release, as per
      # (A PMC member will need to do this)
      svn checkout dist-release-nifi
  5. Make sure your maven settings.xml and settings-security.xml files are configured correctly to sign build artifacts, as described in Appendix B: Configure GPG, Maven, and Git for Signing and Deploying.

Appendix B: Configure GPG, Maven, and Git for Signing and Deploying

This sections assumes that you have already completed the steps in Appendix A: First Time Release Manager Prep in order to generate a code signing key pair. Generating the signing keys is a one time step; so long as your key is not comprised or otherwise invalid it can be used for multiple releases. The following settings need to be configured before every release (or at least checked that they do not need to be changed) in order to make sure that the steps that perform a PGP signature will work correctly.

GPG Settings

If you use a different GPG home directory for code signing, enable that:

export GNUPGHOME=/path/tp/code-signing-gnupg-home

# Note: 
# - Verify this setting by running `gpg --version`
# - Confirm your code signing key by running `gpg --list-keys <email_address>`
# - To clear this env var and revert this, use `unset GNUPGHOME`, or just terminate the shell session and create a new one.

(Recommended) Configure GPG to always prefer stronger hashes:

Note that you may have to configure this in order for Maven to prompt you for your private key passphrase:

GPG_TTY=$(tty) && export GPG_TTY

Maven Settings

To perform a release, your Maven settings.xml, typically located in your ~/.m2 directory, must be updated to include a signed_release profile and a server entry for

<settings xmlns="" 



Encrypting Passwords in Maven settings.xml

Steps to configure and encrypt Maven passwords are available at:

There are other ways to ensure your PGP key is available for signing as well.

Git Settings

During the RM process, git will use your code signing private key in order to sign commits and tags. To facilitate this, configure the git user.signingkey property, such as:

# Check the current value (you may want to make a note of it so that you can revert this setting after you are done the release):
git config --global user.signingkey

# Set a temporary value for your code signing key:
git config --global user.signingkey CODE_SIGNING_KEY_FINGERPRINT

# Discover your CODE_SIGNING_KEY_FINGERPRINT by running `gpg --list-keys <email_address>`
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