Teaching vacancies - Rollback

It is possible to deploy a specific tag to an environment.

If you need to rollback manually, here are the steps required for each type of failure.

Code

The simplest approach to rollback the code to a working version is to revert a pull request on GitHub. This will create a new PR that once is merged triggers a deploy.

Data

Ideally database schema changes are decorrelated from application deployments. So if one has to be rolled back, it doesn't impact the other.

See current version of database

make production rake task=db:version CONFIRM_PRODUCTION=YES

Rollback last n migrations

Given the current state of the database, figure out the version of the database you want to rollback to, and see how many steps you want to rollback.

make production rake task=db:rollback STEP=n CONFIRM_PRODUCTION=YES

If it's only the last migration that you are not happy with, remove STEP=n

Bear in mind that if a migration fails, the current state of the database will be the previous migration. The failing migration could have partially run, in that case you have to fix the data manually.

Restore nightly backup

TBD

Restore point-in-time backup

TBD

Restore from S3 backup

TBD