How to set redis DB ID in Docker container?

[ryanerwin]

@sam is your warning from 2018 about the message bus exclusively linked to Redis db 0 still accurate, or can we use now a different redis instance database ID to host different discourse instances?

I noticed in the multisite-configuration-with-docker howto, there is a db_id: 2 defined, I thought that may refer to the redis database ID, thus this inquiry

         secondsite:
           adapter: postgresql
           database: b_discourse
           pool: 25
           timeout: 5000
           db_id: 2
           host_names:
             - b.discourse.example.com

@TomekB

Without this the stats reported in Admin → Reports are mixed up between different forums

@rluba

It’s called redis_db , so the corresponding setting in the container yaml should be DISCOURSE_REDIS_DB .

@sam

Definitely do not do anything like this . Message Bus which is responsible for long polling relies on pub/sub, pub/sub is always on “db 0” not configurable.

If you try to co-host multiple Discourses on one Redis DB expect some very major amount of breakage.