Add Standards/scs-0104-v2-standard-images.md (#989)

* Add Standards/scs-0104-v2-standard-images.md

Signed-off-by: Matthias Büchse <matthias.buechse@alasca.cloud>

* Clarify or remove tables

Signed-off-by: Matthias Büchse <matthias.buechse@alasca.cloud>

* Remove trailing space

Signed-off-by: Matthias Büchse <matthias.buechse@alasca.cloud>

* Extend properties for standard CAPI image

Co-authored-by: Kurt Garloff <kurt@garloff.de>
Signed-off-by: Matthias Büchse <matthias.buechse@alasca.cloud>

* Add replaces field to front matter

Signed-off-by: Matthias Büchse <matthias.buechse@alasca.cloud>

* update website

Signed-off-by: Marvin Frommhold <depressiveRobot@users.noreply.github.com>

* Update Standards/scs-0104-v2-standard-images.md

Signed-off-by: Kurt Garloff <kurt@garloff.de>

---------

Signed-off-by: Matthias Büchse <matthias.buechse@alasca.cloud>
Signed-off-by: Marvin Frommhold <depressiveRobot@users.noreply.github.com>
Signed-off-by: Kurt Garloff <kurt@garloff.de>
Co-authored-by: Kurt Garloff <kurt@garloff.de>
Co-authored-by: Marvin Frommhold <depressiveRobot@users.noreply.github.com>

Author: 3 people

Standards/scs-0104-v2-standard-images.md

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+---
+title: SCS Standard Images
+type: Standard
+status: Draft
+track: IaaS
+description: |
+  The SCS-0104 standard establishes guidelines for virtual machine images in Sovereign Cloud Stack (SCS)
+  environments, specifying mandatory as well as recommended images, ensuring interoperability and streamlined
+  deployments. It mandates that image upload via Glance must be allowed, ensuring flexibility for users.
+replaces: scs-0104-v1-standard-images.md
+---
+
+## Introduction
+
+The [Sovereign Cloud Stack (SCS)](https://sovereigncloudstack.org/) provides standards for a range of cloud infrastructure types.
+It strives for interoperable and sovereign cloud offerings which can be deployed and used by a wide range of organizations and individuals.
+
+To this end, SCS unifies the naming and sourcing of virtual machine images, and for certain images their presence is mandated or recommended.
+
+## Uploading custom images
+
+Image upload via Glance MUST be allowed based on a fair-use policy.
+
+## Mandatory image sources
+
+### Generic OS images
+
+For an OS image with `os_purpose=generic`, the `image_source` SHOULD come from the original vendor. This allows the user to download and inspect the image.
+Specifically, the following forms are even REQUIRED:
+
+| `os_distro` | `os_version` | permissible `image_source` form(s) |
+| --- | --- | ----|
+| debian | [N]N | `https://cloud.debian.org/images/cloud/{codename}/...` |
+|        |   | `https://cdimage.debian.org/cdimage/cloud/{codename}/...` |
+| ubuntu | NN.NN | `https://cloud-images.ubuntu.com/releases/{codename}/...` |
+|        |       | `https://cloud-images.ubuntu.com/{codename}/...` |
+
+### Official SCS CAPI images
+
+For each image whose name matches the regular expression
+
+    ubuntu-capi-image( |-)v[0-9]\.[0-9]+(\.[0-9]+)?
+
+the following property values MUST be set:
+
+| property | value (pattern) |
+| --- | --- |
+| `image_source` | `https://nbg1.your-objectstorage.com/osism/openstack-k8s-capi-images/...` |
+| | (tolerable for compatibility): `https://swift.services.a.regiocloud.tech/swift/v1/AUTH_b182637428444b9aa302bb8d5a5a418c/openstack-k8s-capi-images/...` |
+| `os_purpose` | `k8snode` |
+| `image_description` | `https://github.com/osism/k8s-capi-images` |
+
+CSPs are free to register CAPI images with a different naming scheme from different source.
+
+## Mandatory and recommended images
+
+The tables in this section show what images are required or recomended.
+
+Note that this standard does not prohibit any images, and neither
+does it preclude the operator from providing any and all optional images,
+so long as they do not violate above regulations on image sources.
+
+### Generic OS images
+
+Each row of the following table describes an image that MUST or SHOULD exist,
+depending on the value in the column 'status'.
+
+| status | os_distro | os_version | os_purpose |
+| --- | --- | --- | --- |
+| required | `ubuntu` | latest LTS, no later than April 30 | `generic` |
+| recommended | `ubuntu` | previous LTS | `generic` |
+| recommended | `debian` | latest stable, no later than one month after release | `generic` |
+| recommended | `debian` | previous stable | `generic` |
+
+A generic OS image MAY be named in the form "distro version",
+without codename or build date; for instance,
+
+- `Ubuntu 24.04`,
+- `Debian 13`.
+
+Note: when a new LTS/stable version is released and the respective image added to the environment,
+the images of any previous versions may or may not be kept.
+
+### Official SCS CAPI images
+
+An image whose name matches the regular expression
+
+    ubuntu-capi-image-v[0-9]\.[0-9]+(\.[0-9]+)?
+
+SHOULD be present.