Release Process

Metron Release Types

There are two types of Metron releases:

• Feature Release (FR) - this is a release that has a significant step forward in feature capability and is denoted by an upgrade of the second digit
• Maintenance Release (MR) - this is a set of patches and fixes that are issued following the FR and is denoted by an upgrade of the third digit

Release Naming Convention

Metron build naming convention is as follows: 0.[FR].[MR].  We keep the 0. notation to signify that the project is still under active development and we will hold a community vote to go to 1.x at a future time.  The first release in a Feature Release line is 0.[FR].0.  There may or may not ever be a release 0.[FR].1, depending whether the community decides to create follow-on Maintenance Release(s) or just go straight to the next Feature Release (which would be named 0.[FR+1].0).

Creating a Feature Release

Step 1 - Initiate a [DISCUSS] thread

Prior to the release the Release manager should do the following (preferably starting about a month before the release):

• Make sure that the list of JIRAs slated for the release accurately reflects the pull requests that are currently in master
• Construct an email to the Metron dev board (dev@metron.apache.org) which discusses with the community the desire to do a release. This email should contain the following:
  
  • The version number for the new release to be.
  • Proposed timeframe for the code freeze and release.
  • The list of JIRAs already committed for the release, with descriptions.

(See "CHANGES file" below for a grep command that will generate the list of JIRAs already committed.)

• • A solicitation of additional JIRAs that would be desirable to include in the next release. Users should rate them as must-have / should-have  / good-to-have, as well as volunteering.

A release email template is provided here.

Step 2 - Monitor and Verify JIRAs

Once the community votes for additional JIRAs they want included in the release verify that the pull requests are in before the release, close these JIRAs and tag them in the JIRA app with the release name. All pull requests and JIRAs that were not slated for this release will go into the next releases.  The release manager should continue to monitor the JIRA to ensure that the timetable is on track until the release date.  On the release date the release manager should message the Metron dev board (dev@metron.apache.org) announcing the code freeze for the release. 

Step 3 - Increment Metron version if needed

Determine the current build version number on master branch, as described here.  If it is not the desired release number (for instance, if we desire to release version 0.5.0, but the current build version is 0.4.1), then submit a PR to update the build version number as described in Change the Build Version Number, get approval, and commit.

Step 4 - Create the Release Branch

Create a branch for the release (from a git repo cloned from https://git-wip-us.apache.org/repos/asf/metron.git). All the example commands below assume the desired release is 0.[FR].0:

git checkout master
git checkout -b Metron_0.[FR].0
git push --set-upstream origin Metron_0.[FR].0

Also, the release manager should have a couple of things set up:

• A SVN clone of the repo at https://dist.apache.org/repos/dist/dev/metron, We will refer to this as the dev repo.  It will hold the release candidate artifacts
• A SVN clone of the repo at https://dist.apache.org/repos/dist/release/metron, We will refer to this as the release repo.  It will hold the release artifacts.

Step 5 - Create the Release Candidate

Now, for each release candidate, we will tag from that branch. Assuming that this is RC1 (the first Release Candidate):

git checkout Metron_0.[FR].0 && git pull
git tag apache-metron-0.[FR].0-rc1
git push --tags origin 

We will refer to this as the release candidate tarball. Notes:

• Per Apache policy, the hardware used to create the candidate tarball must be owned by the release manager.
• It often takes several Release Candidates to achieve an approved release.  Be careful to keep incrementing the "rc#" on all artifacts in each generation, so as to avoid confusion.

The artifacts for a release (or a release candidate, for that matter) are as follows:

• Release (candidate) Tarball
• MD5 hash of the release tarball.  (md5 apache-metron-0.[FR].0-rc1.tar.gz > apache-metron-0.[FR].0-rc1.tar.gz.md5)
• We used to use SHA1 hash digests in the signing process.  Per Apache guidance, we should now use SHA512; see here for how to set your gpg defaults, and upgrade your signing keys if you have old ones.  Likewise, do not use 4-byte fingerprints, like "DEAD BEEF" or "0xDEADBEEF", to refer to your signing key, as these have been demonstrated vulnerable.  Instead use 8-byte fingerprints, like "BADD CAFE DEAD BEEF" or "0xBADDCAFEDEADBEEF".
• SHA512 hash of the release tarball; here we will also provide SHA1 and SHA256 hashes for backward compatibility:
  • gpg --print-md SHA512 apache-metron-0.[FR].0-rc1.tar.gz > apache-metron-0.[FR].0-rc1.tar.gz.sha512
  • gpg --print-md SHA256 apache-metron-0.[FR].0-rc1.tar.gz > apache-metron-0.[FR].0-rc1.tar.gz.sha256
  • gpg --print-md SHA1 apache-metron-0.[FR].0-rc1.tar.gz > apache-metron-0.[FR].0-rc1.tar.gz.sha1
  • cp apache-metron-0.[FR].0-rc1.tar.gz.sha1 apache-metron-0.[FR].0-rc1.tar.gz.sha
• GPG signature of release tarball by the release manager
•  Assuming your 8-byte public code signing key fingerprint is 0xBADDCAFEDEADBEEF, so your signing command would be: gpg -u 0xBADDCAFEDEADBEEF --armor --output apache-metron-0.[FR].0-rc1.tar.gz.asc --detach-sig apache-metron-0.[FR].0-rc1.tar.gz
• Note: You only need the -u arg if you have more than one public/private key pair generated.  If you have forgotten it, you can find it from the output of gpg —fingerprint.  It’s the last 8 bytes (16 hex characters) from the key fingerprint.
• If you do not know, or cannot recover, your code signing key and password as release manager, you must start over with a new code signing key. Follow the instructions at https://www.apache.org/dev/release-signing.html#generate .  You should then link your new code signing key into Apache's web of trust.
• The LICENSE file from the release tarball
• The KEYS file from the release tarball
• A CHANGES file denoting the changes
• We usually construct this by taking the output of git log | grep METRON | sed 's/\[//g' | sed 's/\]//g' | grep -v "http" and removing the JIRAs from the previous releases (it’s in time sorted order so this is easy).

Create a directory named ${VERSION}-RC${RC_NUM} (in our case, it’s 0.[FR].0-RC1) in the dev repo.  Place the artifacts from above into this directory, add the directory and commit via the subversion client:

svn add 0.[FR].0-RC1
svn commit -m "Adding artifacts for Metron 0.[FR].0-RC1"

Step 6 - Verify the build

Go through the build verification checklist to verify that everything works.  These instructions can be found here: Verifying Builds

Step 7 - Verify licensing

Make sure the release complies with the following Apache licensing guidelines: http://www.apache.org/foundation/license-faq.html

Step 8 - Call for a community release vote

Next initiate a [VOTE] thread on the dev list to announce the build vote.  The vote email template can be found here: Build Vote Template.  Allow at least 72 hours for the community to vote on the release.

• If issues are found with the release and the vote fails, then the vote thread is closed with a synopsis of the voting results and a new RC is worked on in the community

• If issues are found with the release and the vote succeeds, then we proceed to cut the release, but should notify the community of the issues via an email on the dev list with the accompanying JIRA(s) required to correct the issue(s).

• If no issues are found, then we can cut a release

When you get enough votes, close the vote by replying [RESULT][VOTE] to the email thread with the tally of all the votes.  Again, wait for at least 72 hours before closing the vote.

Step 9 - Tag the finished release

After the vote passes, re-tag the RC as the release.  In your working repo for the release (cloned from https://git-wip-us.apache.org/repos/asf/metron.git), do:

git tag  apache-metron-0.[FR].0-release  apache-metron-0.[FR].0-rc1
git push --tags origin

Step 10 - Stage the finished release

A directory with the name of the release version should be made in the release svn repository

Collateral from the release candidate in the dev repo should be moved to the release repo directory and renamed to remove the rc (e.g. mv apache-metron-0.[FR].0-rc1.tar.gz.sha apache-metron-0.[FR].0.tar.gz.sha)

Add the directory and commit via the subversion client:

svn add 0.[FR].0
svn commit -m "Adding artifacts for Metron 0.[FR].0"

Confirm that the new release is visible in dist, by pointing your browser at https://dist.apache.org/repos/dist/release/metron/ .  It should appear promptly, but may not be instantaneous.

Step 11 - Update the Website to point at the new release location

Instructions are here: Website PR Merge.  Do the changes, submit a PR, get approval, and commit the new "site" source to master.  But don't do the final step yet (commit built site image from "target" to asf-site branch), until the release has propagated to mirrors.

Remember that download links in the Website should never point directly at dist, but rather always point at mirrors via http://www.apache.org/dyn/closer.cgi/metron/[VERSION]/...  However, the signature files (.asc, .sha, and .md5) must point directly at dist.

Step 12 - Wait for the new release to propagate to mirrors

According to Apache docs, "It may take up to 24 hours or more for a newly published release to be sync'd to all mirrors. Mirrors have their own schedules. Mirrors are required to check at least once a day, but most will check for updates 2 to 4 times per day."  At least wait until a spot-check of mirrors on http://www.apache.org/dyn/closer.cgi/ show the new release.

Step 13 - Announce the release

Commit the built Website to the Metron asf-site branch, per the final instructions from Website PR Merge, so it is publicly visible.

Send an email out to user@ and dev@ to announce the release along with the changelog and a word of thanks/praise.

Step 14 - Clean up

Remove the old releases from the release repo, after making sure they are already mirrored into the archive repo.  Only the current version and the KEYS file should be in the release repo.

It is good practice to increment the build version in master immediately after a Feature Release, so that dev builds with new stuff from master cannot be mistaken for builds of the release version. So, immediately after a release, increment the MINOR version number (eg, with the 0.4.0 just released, set the new version number to 0.4.1) per Change the Build Version Number.

Creating a Maintenance Release

Creation of the Maintenance Release should follow exactly the same set of steps as creating the Feature Release as outlined above, but with two exception.  First, the version incremented on the maintenance release should be the MR++ so that the release is named 0.[FR].[MR++].  Second, if a critical JIRA comes in that requires an immediate patch, the votes with three binding +1's are still required, but the following can be waived:

• Step 1 (discussion)
• Step 2 (Jira collecting and tracking)
• the 72 hour waiting period in Step 8 (vote)
• Step 12 (mirror propagation)

A critical JIRA is something that is either a security vulnerability or a functional show stopper.

Maintaining a Maintenance Branch

Being able to maintain the previous release train, with only critical or important bug fixes and security fixes (generally not new features) for users who are averse to frequent large changes is very important for production use.  They get stability, while the new feature release code line proceeds as fast as the community wishes.  

When needed, and with community discussion, create a Maintenance Branch for the previous Metron release by incrementing the *third* digit of the previous release like so 0.[FR].[*MR++*].  All patches to the previous Metron release will be checked in under the MR branch and where it makes sense also under the master branch.  All new features will be checked in under the master branch.

Ensuring Consistency between Feature and Maintenance releases

It is important to assure that all commits to the maintenance branch also get made in the master branch (if relevant), to avoid the appearance of regressions in the next Feature Release from master branch.  The formal process for assuring this is as follows:

• Every maintenance release JIRA should have a corresponding feature JIRA to make sure that the patch is applied consistently to both branches.  The maintenance JIRA should be cloned and appropriate fix version for the feature release should be applied.  If the fix is not relevant to the feature or maintenance branch then the submitter must explicitly state this.  In general reviewers should refuse a maintenance branch patch PR unless both feature and maintenance JIRAs have been created.
• The release manager has a responsibility to review all commits to the maintenance line since last release, and make sure they were duplicated to the feature branch (unless not relevant, which must also be determined).