Discussion on: How does your team handle critical production errors?

We use Sentry to make sure we get notified directly if something goes wrong.

What to Do?

If there is NO migration made (no db changes) in the latest deployed release:

1. We run a container from our previous docker image.
2. Let Nginx's load balancer do its magic to load the traffic from the bad container into the good one.
3. Fix the issue and make sure things work fine before deploying 😁
4. Repeat from 1 to 2, but with the new bug-free-hopefully container.

If there is migration made (db changes made to existing data... not happening so often):

1. Realize that you fu**ed up this time (cuz you can't use an old container)!
2. Fix it fast.
3. Deploy again.