Releases

Last updated 17 December 2015

Whenever you deploy code, change a config var, or add or remove an add-on resource, Heroku creates a new release and restarts your app. You can list the history of releases, and use rollbacks to revert to prior releases for backing out of bad deploys or config changes.

Release creation

Releases are named in the format vNN, where NN is an incrementing sequence number for each release.

Releases are created whenever you deploy code. In this example, v10 is the release created by the deploy:

$ git push heroku master
...
-----> Compressing... done, 8.3MB
-----> Launching... done, v10
       http://severe-mountain-793.herokuapp.com deployed to Heroku

Releases are created whenever you change config vars. In this example, v11 is the release created by the config change:

$ heroku config:set MYVAR=42
Adding config vars:
  MYVAR => 42
Updating vars and restarting app... done, v11

Releases are created whenever you add, remove, upgrade, or downgrade add-on resources. In this example, v12 is the release created by the add-on change:

$ heroku addons:create memcachier
Adding memcachier to myapp... done, v12 (free)

Listing release history

To see the history of releases for an app:

$ heroku releases
Rel   Change                          By                    When
----  ----------------------          ----------            ----------
v52   Config add AWS_S3_KEY           jim@example.com       5 minutes ago
v51   Deploy de63889                  stephan@example.com   7 minutes ago
v50   Deploy 7c35f77                  stephan@example.com   3 hours ago
v49   Rollback to v46                 joe@example.com       2010-09-12 15:32:17 -0700

The number next to the deploy message, for example de63889, corresponds to the commit hash of the repository you deployed to Heroku. Use this to correlate changes in a release with a changes in your code repository. For example:

$ git log -n 1 de63889
commit de63889c20a96347679af2c5160c390727fa6749
Author: <stephan@example.com>
Date:   Thu Jul 11 17:16:20 2013 +0200
Fixed listing CSS and localization of description.

To get detailed info on a release:

$ heroku releases:info v24
=== Release v24
Change:      Deploy 575bfa8
By:          jim@example.com
When:        6 hours ago
Addons:      deployhooks:email, releases:advanced
Config:      MY_CONFIG_VAR => 42
             RACK_ENV      => production

Rollback

Use the rollback command to roll back to the last release:

$ heroku rollback
Rolled back to v51

You may choose to specify another release to target:

$ heroku rollback v40
Rolled back to v40

Rolling back will create a new release which is a copy of the state of the compiled slug and config vars of the release specified in the command. The state of your heroku Git remote, database, and external state held in add-ons (for example, the contents of memcache) will not be affected and is your responsibility to reconcile with the rollback.

Running on a rolled-back release is meant as a temporary fix to a bad deployment. If you are on a rolled-back release, fix and commit the problem locally, and re-push to Heroku to update the heroku Git remote and create a new release.