Fastapi recommends use gunicorn with uvicorn workers why?

First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn’t find it.
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Example Code

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def root():
    return {"message": "Hello World"}

Description

Currently i use uvicorn only in production but when i check the docs it says you should run uvicorn workers inside gunicorn, what do i get when i replace it with gunicorn?

Operating System

Linux

Operating System Details

No response

FastAPI Version

latest

Python Version

3.9

Additional Context

No response

[adriangb]

I think it’s important to look at the bigger picture in a production setup. If you’re running containerized, replicated deployments on k8s, you don’t really need a process manager for resiliency or upgrades. What you do need however is good load balancing, and Gunicorn / Uvicorn workers (well, really the OS itself) provide that. k8s load balancing is just iptables by default I believe, so not even round robin.

[insomnes]

You can read exactly what you search in uvicorn documentation: https://www.uvicorn.org/deployment/#using-a-process-manager