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

Question

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

User · Accepted Answer

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  amp  amp  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

User · Answer

The commands are adduser and addgroup   Here s a template for Docker you can use in busybox environments  alpine  as well as Debian-based environments  Ubuntu  etc     ENV USER docker ENV UID 12345 ENV GID 23456  RUN adduser       --disabled-password       --gecos          --home    pwd         --ingroup   USER        --no-create-home       --uid   UID          USER    Note the following    --disabled-password prevents prompt for a password --gecos    circumvents the prompt for  Full Name  etc  on Debian-based systems --home    pwd   sets the user s home to the WORKDIR  You may not want this  --no-create-home prevents cruft getting copied into the directory from  etc skel   The usage description for these applications is missing the long flags present in the code for adduser and addgroup   The following long-form flags should work both in alpine as well as debian-derivatives   adduser  BusyBox v1 28 4  2018-05-30 10 45 57 UTC  multi-call binary   Usage  adduser  OPTIONS  USER  GROUP   Create new user  or add USER to GROUP          --home DIR           Home directory         --gecos GECOS        GECOS field         --shell SHELL        Login shell         --ingroup GRP        Group  by name          --system             Create a system user         --disabled-password  Don t assign a password         --no-create-home     Don t create home directory         --uid UID            User id   One thing to note is that if --ingroup isn t set then the GID is assigned to match the UID  If the GID corresponding to the provided UID already exists adduser will fail   addgroup  BusyBox v1 28 4  2018-05-30 10 45 57 UTC  multi-call binary   Usage  addgroup  -g GID   -S   USER  GROUP  Add a group or add a user to a group          --gid GID  Group id         --system   Create a system group   I discovered all of this while trying to write my own alternative to the fixuid project for running containers as the hosts UID GID   My entrypoint helper script can be found on GitHub   The intent is to prepend that script as the first argument to ENTRYPOINT which should cause Docker to infer UID and GID from a relevant bind mount   An environment variable  TEMPLATE  may be required to determine where the permissions should be inferred from    At the time of writing I don t have documentation for my script  It s still on the todo list

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

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