• DockerContainerUser

DockerContainerUser

• By default docker runs with the user in the container as root 0:0 having full access to stuff in the container, including mounted directories.

Specify specific user

• Why ?
  • When using docker to just build local code, mounting it into a nodejs / java / python container, we want the artifacts left in the mounted directory to be owned by the local users
• How ?
  • -u ubuntu:ubuntu docker flag to set user.

  • more generic  --user $(id -u ${USER}):$(id -g ${USER})  

  • e.g

    docker container run --rm \
        -v ${PWD}:/var/www \
        -w /var/www \
        -u $(id -u ${USER}):$(id -g ${USER}) \
        mycontainer/python:7.2 composer 

Using user in Dockerfile

• When building docker containers a default user can be set, normally this will be 1000:1000.
• This is normally done to the end of the docker definition to allow root to update packages before switching to user.