jpf91/fedora-systemd

This image provides a systemd (base) image based on the latest fedora release.

It can be either used as a base image for other systemd based containers or as a standalone image to run systemd timers and other units. It provides the following features:

Redirects journal logs to console so they show up in podman / docker logs
Disables TTY login
Allows running scripts on each container start
Allows running scripts on first container start
Can send emails

Supported Architectures

Currently only x86_64 images are being built, allthough the Dockerfile is not architecture dependent.

Usage

As base image

If you just want to use this image as a base image:

# https://fedoramagazine.org/building-smaller-container-images/
FROM docker.io/jpf91/fedora-systemd

# Install your packages
RUN microdnf install \
    nano && \
    microdnf clean all

# Add a script which is run once on first container start (extension must be .sh)
ADD 01-setup-script.sh /etc/initial-setup.d/01-setup-script.sh

# Add a script which is run on every container start (extension must be .sh)
ADD 01-start-script.sh /etc/initial-setup.d/01-start-script.sh

Running using podman cli

podman run --name systemd -t \
  -v $PWD/systemd-email.conf:/etc/systemd-email.conf \
  -v $PWD/ssmtp.conf:/etc/ssmtp/ssmtp.conf \
  -v $PWD/services:/etc/systemd/user-units \
  -v $PWD/start:/etc/start-scripts.user.d \
  -v $PWD/setup:/etc/initial-setup.user.d \
  docker.io/jpf91/fedora-systemd

Here's an example to run startup scripts and a custom systemd timer:

test/services/test.timer:

[Unit]
Description=Test Timer

[Timer]
OnCalendar=*:0/1

[Install]
WantedBy=timers.target

test/services/test.service:

[Unit]
Description=Test Unit

[Service]
Type=oneshot
ExecStart=/usr/bin/echo Test Unit Executing

test/setup/01-setup.sh:

#!/bin/sh
echo "Running Setup"

systemctl enable --now test.timer

test/start/01-echo.sh:

#!/bin/sh

echo "This is a start script"

Sending status emails

This image has ssmtp installed which can be used to send status reports. First you have to provide a ssmtp configuration:

mailhub=smtp.gmail.com:587
rewriteDomain=gmail.com

# Use SSL/TLS before starting negotiation
TLS_CA_FILE=/etc/ssl/certs/ca-bundle.crt
UseTLS=Yes
UseSTARTTLS=Yes
AuthUser=username
AuthPass=password
AuthMethod=LOGIN
FromLineOverride=yes

Configure the container using the systemd-email.conf file to set the email address to send to:

MAIL_TO=foo@example.com
MAIL_FROM_DOMAIN=example.com
MAIL_FROM_USER=nas

Then in your systemd units, add something like the following:

[Unit]
OnFailure=systemd-email@%n.service

# or to always run after a job succeeded:
ExecStartPost=/etc/systemd-email.sh systemd %n

Parameters

Container images are configured using parameters passed at runtime (such as those above). These parameters are separated by a colon and indicate <external>:<internal> respectively. For example, -p 22:22 would expose port 22 from inside the container to be accessible from the host's IP on port 22 outside the container.

Parameter	Function
`-t`	In order for logging to work, a terminal needs to be allocated.
`-/etc/systemd-email.conf`	Systemd status emails configuration, see above.
`/etc/ssmtp/ssmtp.conf`	ssmtp configuration to send emails.
`-v /etc/systemd/user-units`	Place systemd service files here. Files will be symlinked to `/etc/systemd/system` once on first container start. See above for an example.
`-v /etc/start-scripts.user.d`	Place bash scripts here (extension `.sh`) which will be executed at every container start.
`-v /etc/initial-setup.user.d`	Place bash scripts here (extension `.sh`) which will be executed at initial container start.

Support Info

Shell access whilst the container is running: podman exec -it systemd /bin/bash
To monitor the logs of the container in realtime: podman logs -f systemd.
Report bugs here.

Building locally

If you want to make local modifications to these images for development purposes or just to customize the logic:

git clone https://github.com/jpf91/docker-fedora-systemd.git
cd docker-fedora-systemd
podman build \
  -t docker.io/jpf91/fedora-systemd:latest .

Versions

05.04.21: - Initial Release.