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29 August 2014
How We Run as a Non-Root Inside Docker Container
Docker starts a process inside its container as a "root" user. In some
cases, this is not convenient though. For example,
initdb from PostgreSQL doesn't like to
be started as root and will fail. In rultor.com,
a DevOps team assistant,
we're using Docker
as a virtualization technology for every build we run.
Here is how we change the user inside a running container, right after it is started.
First, this is how we start a new Docker container:
$ sudo docker run -i -t --rm -v "$(pwd):/main" \ yegor256/rultor /main/entry.sh
There are two files in the current directory:
entry.sh is the file being executed by Docker on start,
and it contains the following:
#!/bin/bash adduser --disabled-password --gecos '' r adduser r sudo echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers su -m r -c /home/r/script.sh
script.sh will be executed as a user
r inside the container. And this
r user will have
sudo permissions. This is exactly what all projects,
managing their DevOps procedures with rultor.com, need.