andrewmackrodt/ubuntu repository overview

⁠andrewmackrodt/docker-ubuntu⁠

Ubuntu⁠ 22.04 (Jammy) base image.

⁠Features

• Default non-root user account ubuntu with optional passwordless sudo
• Configurable UID via environment variable
• Configurable GID via environment variable
• Configurable timezone via environment variable
• Automatic init using tini⁠ or s6-overlay⁠ to reap zombies
• Automatic step down from root to ubuntu via gosu⁠

⁠Usage

All images (unless explicitly mentioned in their documentation) run as the user ubuntu with the working directory /home/ubuntu.

⁠Entrypoint

Containers use the entrypoint /usr/local/bin/docker-entrypoint.sh which elevates itself as root, configures the UID, GID and timezone and starts the init system (tini or s6-overlay depending on the container). Finally, gosu is used to step down to the ubuntu user before executing the container specific entrypoint (defined by environment variable ENTRYPOINT0) or user command.

⁠PID 1

Under normal operation PID 1 will be the sudo command which invokes the init system. In my testing, signal processing propagates correctly to the tini or s6-overlay processes which are the only other top-level processes. However, it is also possible to start the container with the option --user root which will make the init process PID 1. Note that docker exec will run as root if this option is specified.

$ docker run --rm andrewmackrodt/ubuntu -c "id -a; date; ps faux"

uid=1000(ubuntu) gid=1000(ubuntu) groups=1000(ubuntu),4(adm)
Wed May 15 13:55:25 UTC 2019
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0  47704  3496 ?        Ss   13:55   0:00 sudo -E tini -s -g /usr/local/bin/docker-entrypoint.sh -- -c id -a; date; ps faux
root         8  0.0  0.0   4520   752 ?        S    13:55   0:00 tini -s -g /usr/local/bin/docker-entrypoint.sh -- -c id -a; date; ps faux
ubuntu       9  0.0  0.0  18376  2816 ?        S    13:55   0:00  \_ /bin/bash -c id -a; date; ps faux
ubuntu      61  0.0  0.0  34400  2792 ?        R    13:55   0:00      \_ ps faux

$ docker run --rm --user root andrewmackrodt/ubuntu -c "id -a; date; ps faux"

uid=1000(ubuntu) gid=1000(ubuntu) groups=1000(ubuntu),4(adm)
Wed May 15 13:56:21 UTC 2019
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
ubuntu       1  3.0  0.0   4520   724 ?        Ss   13:56   0:00 tini /bin/bash -- -c id -a; date; ps faux
ubuntu      48  0.0  0.0  18376  2968 ?        S    13:56   0:00 /bin/bash -c id -a; date; ps faux
ubuntu      51  0.0  0.0  34400  2860 ?        R    13:56   0:00  \_ ps faux

⁠Parameters

General parameters supported by all inherited images

Additional parameters for image builders