How stateful are both the frontend and backend?

[Kernald]

Assuming one is using an external Postgres database - how stateful are the containers? Would there be anything preventing spinning up e.g. two frontends and two backends with a round-robin between requests?

[TomBursch]

Hi, yes, they are mostly statless. But you will need to set up a rabbitmq for job orchestration. See https://github.com/TomBursch/kitchenowl/blob/main/docker-compose-rabbitmq.yml

Additionally, for real-time sync you cannot use round-robin but sticky session:

The load balancer must be configured to forward all HTTP requests from a given client always to the same worker. This is sometimes referenced as “sticky sessions”. For nginx, use the ip_hash directive to achieve this. Gunicorn cannot be used with multiple workers because its load balancer algorithm does not support sticky sessions.

Taken from https://flask-socketio.readthedocs.io/en/latest/deployment.html#using-multiple-workers

I haven't actually tested this, though, some dependencies could be missing.

[Kernald]

Thanks for this! I'll likely try to give this a shot in the upcoming weeks, I'll post my findings here.