Editing One Quick Way To Host A WebApp (section)

==== Quadlets ====

I used to use Podman and then write a traditional systemd unit file to manage the container as if it were a service. I liked that approach because the fact that it was in podman was an implementation detail of the app. I could just as well have it a bare binary doing the same thing and I'd run the same `systemctl` command.

I later discovered systemd quadlets: containers managed by systemd itself. These are quite nice since you write them in a format that is like a unit file and you can use your usual systemctl commands to manage them directly. Here's an example quadlet configuration.

<syntaxhighlight lang="ini">
[Unit]
Description=MediaWiki Container
After=network-online.target
Wants=network-online.target

[Container]
Image=localhost/wiki.roshangeorge.dev:latest
ContainerName=rowik
Environment=MEDIAWIKI_DB_TYPE=mysql
PublishPort=127.0.0.1:8080:80
Volume=/mnt/r2/uploads:/var/www/html/images:Z
AutoUpdate=registry

[Service]
Restart=always
TimeoutStartSec=300

[Install]
WantedBy=multi-user.target default.target
</syntaxhighlight>

One debug annoyance is that viewing quadlet startup logs is not straightforward if you have made an error in quadlet configuration. Instead of an error in your service, it is a syslog error on the unit file generator. This is because when a quadlet is configured like this, what happens is that systemd has a generator that converts it to a service file on the fly and then runs that, so if you have a configuration error here it isn't marked against the service and so you'll just get a 'service not found'. Regardless, I find quadlets nicer to manage than writing a run script and a systemd unit file around that script.