[SOLVED] How do I add a user when I'm using Alpine as a base image?

How do I add a user when I'm using Alpine as a base image?

I'm using alpine (or an image that is based on Alpine) as the base image in my Dockerfile. Which instructions do I need to add to create a user?

Eventually I'll use this user to run the application I'll place into the container so that the root user does not.

Solution

Alpine uses the command adduser and addgroup for creating users and groups (rather than useradd and usergroup).

FROM alpine:latest

# Create a group and user
RUN addgroup -S appgroup && adduser -S appuser -G appgroup

# Tell docker that all future commands should run as the appuser user
USER appuser

The flags for adduser are:

Usage: adduser [OPTIONS] USER [GROUP]

Create new user, or add USER to GROUP

        -h DIR          Home directory
        -g GECOS        GECOS field
        -s SHELL        Login shell
        -G GRP          Group
        -S              Create a system user
        -D              Don't assign a password
        -H              Don't create home directory
        -u UID          User id
        -k SKEL         Skeleton directory (/etc/skel)

Add new user official docs