Rootless container quadlet files go under /etc/containers/systemd/users/${UID}/ and the user session will activate the quadlet.
If you put it under etc/containers/systemd/users/ then all user sessions will activate the quadlet
When starting a container unit, systemd may time out due to the time it takes to pull a container. Use the TimeoutStartSec Service option to extend the default 90 second timeout or pre-pill the image.
[Service]
TimeoutStartSec=900
To start a container on boot, the generator manually applies the [Install] section of the container definition unit files during generation in the same way systemctl enable does.
[Install]
WantedBy=default.target
Podman container gets the same name as the container unit file. So nextcloud.container unit file would create a container calle nextcloud.
The Image key is is required and defines the container image that runs.
Example Quadlet file called /etc/containers/systemd/users/SSPR.container
[Unit]
Description=Self Service Password Container
[Container]
Image=docker.io/ltbproject/self-service-password:latest
Volume=/sspr/config.inc.local.php:/var/www/conf/config.inc.local.php:Z
PublishPort=80:80
[Install]
WantedBy=multi-user.target default.target