Issue
I have a private-tier Heroku Redis add-on, and Heroku is frequently updating its config vars every few days:
v51 Update REDIS by heroku-redis heroku-redis@addons.heroku.com 2021/09/07 14:30:51 +0000
v50 Update REDIS by heroku-redis heroku-redis@addons.heroku.com 2021/09/04 15:27:09 +0000
v49 Update REDIS by heroku-redis heroku-redis@addons.heroku.com 2021/09/01 16:17:55 +0000
v48 Update REDIS by heroku-redis heroku-redis@addons.heroku.com 2021/08/29 17:03:06 +0000
v47 Update REDIS by heroku-redis heroku-redis@addons.heroku.com 2021/08/26 18:00:30 +0000
(...)
What is triggering these releases? Is my Heroku Redis add-on going through maintenances?
Resolution
Every time that maintenance runs for your Heroku Redis add-on, Heroku will automatically update your Redis-related config vars and this process will trigger a new release for your app.
If you're using a Private Heroku Redis plan, this means that your Redis instance can only be accessed from dynos in the same Private Space and via a bastion host by users with explicitly granted access to your add-on. This bastion host allows users to use commands like heroku redis:cli to connect to their Private Heroku Redis from an external resource (see: Heroku Redis and Private Spaces: External Connections.
For security reasons, the bastion keys are rotated every 72 hours, approximately. This results in frequent updates to the REDIS_BASTIONS, REDIS_BASTION_KEY and REDIS_BASTION_REKEYS_AFTER config vars, which will be reflected as a Redis update in your app's releases.
If you're seeing frequent releases for your app related to your Redis add-on, you can use heroku releases:info <RELEASE_ID> to compare the differences between some of the releases and confirm if these are due to the bastion config vars changes.