Change effective on 31 March 2016
Today we are pleased to announce that all apps in Private Spaces can now have zero downtime deployments under certain conditions.
Zero downtime is the benefit, while “rolling deploys” is the feature that enables this benefit (analogous to preboot on the Common Runtime). Rolling deploys, enabled by default, rolls out a release to a 25% (rounded up) of the dynos in an existing formation at a time, while traffic is served by the remaining 75%; the release is “rolled out” gradually to the whole formation over several minutes. No special command is necessary to use this feature (e.g, “git push heroku master” will use it assuming there is more than one dyno).
Please see the Dev Center article for details and constraints.