Quadlet: Difference between revisions

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</blockquote><!-- Notes -->
</blockquote><!-- Notes -->
= Syntax =
<blockquote>
== Overview ==
<blockquote>
<syntaxhighlight lang="yaml">
# ~/.config/containers/systemd/${name}.${ext}
# systemd unitfile generator files
*.container: for a single container                        # podman run
*.kube:      from kubernetes yaml files using              # podman kube play
*.pod:      for a single pod within kubernetes yaml files # ? is this correct?
*.yml:      a kubernetes yaml file
# resources
*.image:    ensures a docker image is pulled
*.network:  create podman networks, referenced in '.container' or '.kube' files
*.volume:    create podman volumes, referenced in '.container' files
</syntaxhighlight>
</blockquote><!-- Overview -->
== Standalone Containers ==
<blockquote>
=== *.container ===
<blockquote>
<syntaxhighlight lang="dosini">
# ~/.config/containers/systemd/foo.container
[Install]
WantedBy=default.target
[Container]
Image=docker.io/library/mysql:5.6
ContainerName=foo
Volume=foo.volume:/var/lib/mysql
Network=foo.network
</syntaxhighlight>
</blockquote><!-- *.container -->
</blockquote><!-- Standalone Containers -->
== Kubernetes ==
<blockquote>
=== *.yml ===
<blockquote>
A kubernetes yaml file.
{{ WARN |
this is the official example, haven't had to use this yet
}}
<syntaxhighlight lang="yaml">
# ~/.config/containers/systemd/foo.yml
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: wp-pv-claim
  labels:
    app: wordpress
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
---
apiVersion: v1
kind: Pod
metadata:
  name: quadlet-demo
spec:
  containers:
  - name: wordpress
    image: docker.io/library/wordpress:4.8-apache
    env:
    - name: WORDPRESS_DB_HOST
      value: quadlet-demo-mysql
    - name: WORDPRESS_DB_PASSWORD
      valueFrom:
        secretKeyRef:
          name: mysql-root-password-kube
          key: password
    volumeMounts:
    - name: wordpress-persistent-storage
      mountPath: /var/www/html
# ... etc ...
</syntaxhighlight>
</blockquote><!-- *.yml -->
=== *.pod ===
<blockquote>
Abstraction of a systemd unit file for running specific kubernetes pods only.
{{ TODO |
is this understanding correct?
}}
</blockquote><!-- *.pod -->
=== *.kube ===
<blockquote>
Abstraction of a systemd unit file for running an entire kubernetes project
</blockquote><!-- *.kube -->
</blockquote><!-- Kubernetes -->
== Resources ==
<blockquote>
=== *.network ===
<blockquote>
Define a network to share between multiple containers.
<syntaxhighlight lang="dosini">
# ~/.config/containers/systemd/foo.network
[Network]
Subnet=192.168.30.0/24
Gateway=192.168.30.1
</syntaxhighlight>
would generate
<syntaxhighlight lang="yaml">
podman-network: systmd-foo            # podman network create systemd-foo
systemd-unit:  foo-network.service
</syntaxhighlight>
</blockquote><!-- .network -->
=== *.volume ===
<blockquote>
Describe a volume to share between multiple containers.
By default:
* the volume file <code>${filename}.volume</code> is created
* the podman volume is called <code>systemd-${filename}</code>
* the systemd service is called <code>${filename}-volume.service</code>
<syntaxhighlight lang="dosini">
[Volume]
# all that is required if you want to share the same volume for all containers in a service
</syntaxhighlight>
</blockquote><!-- *.volume -->
=== *.image ===
<blockquote>
Ensure a docker image is pulled.<br>
Generates a service that can be used as a dependency.
</blockquote><!-- *.image -->
</blockquote><!-- Resources -->
</blockquote><!-- Syntax -->


= Examples =
= Examples =

Revision as of 21:37, 18 May 2024

Quadlet is a tool for generating systemd services from podman containers.
You can also describe a project as a podman-compose project, and generate systemd services for it as well.

The goal for the project is to be concise and change tolerant with sane defaults.

Documentation

man quadlet / podman-systemd.unit (incl. filetypes/opts) https://man.archlinux.org/man/quadlet.5.en
official multi-container tutorial https://www.redhat.com/sysadmin/multi-container-application-podman-quadlet
src https://github.com/containers/podman/tree/main/pkg/systemd/quadlet

Tutorials

https://mo8it.com/blog/quadlet/ intro

Locations

~/.config/containers/systemd/* generators for user systemd services (only for rootless podman)
/etc/containers/systemd/* generators for system systemd services
/usr/share/containers/systemd/* generators for system systemd services (installed by packages)
/usr/lib/podman/quadlet quadlet executable (not on path)

Notes

quadlet install
quadlet usage
quadlet syntax
quadlet examples

Examples

quadlet example: single container with volume