How to add users to Docker container?

Question

I have a docker container with some processes (uwsgi and celery) running inside. I want to create a celery user and a uwsgi user for these processes as well as a worker grou

Answer 1

Everyone has their personal favorite, and this is mine:

RUN useradd --user-group --system --create-home --no-log-init app
USER app

Reference: man useradd

The RUN line will add the user and group app:

root@ef3e54b60048:/# id app
uid=999(app) gid=999(app) groups=999(app)

Use a more specific name than app if the image is to be reused as a base image. As an aside, include --shell /bin/bash if you really need.

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Partial credit: answer by Ryan M