Use mand SCS flavors in scs cluster-class template. (#174)

* Use mand SCS flavors in scs cluster-class template.

* Use SCS-2V-4-20s (note the s) as example and default for control plane nodes. We have created the small SSD flavors for exactly this use case, so let's use them. Also note that SCS-2V-4-20 is no longer guaranteed to exist on every SCS (IaaS-compatible-v3+) cloud.
* Likewise shift to SCS-2V-4 (diskless) as default for the worker nodes. This flavor is guaranteed to exist. It will require a root volume, suggest 25GiB.
* Clarify comments on when to use root volumes ...

Signed-off-by: Kurt Garloff <[email protected]>

* Update providers/openstack/scs/cluster-class/templates/cluster-class.yaml

Co-authored-by: Roman Hros <[email protected]>
Signed-off-by: Jan Schoone <[email protected]>

---------

Signed-off-by: Kurt Garloff <[email protected]>
Signed-off-by: Jan Schoone <[email protected]>
Co-authored-by: Jan Schoone <[email protected]>
Co-authored-by: Roman Hros <[email protected]>

providers/openstack/scs/cluster-class/templates/cluster-class.yaml

@@ -46,33 +46,34 @@ spec:
       schema:
         openAPIV3Schema:
           type: string
-          default: "SCS-2V-4-20"
-          example: "SCS-2V-4-20"
+          default: "SCS-2V-4-20s"
+          example: "SCS-2V-4-20s"
           description: "OpenStack instance flavor for control-plane nodes."
     - name: worker_flavor
       required: false
       schema:
         openAPIV3Schema:
           type: string
-          default: "SCS-2V-4-20"
-          example: "SCS-2V-4-20"
+          default: "SCS-2V-4"
+          example: "SCS-2V-4"
           description: "OpenStack instance flavor for worker nodes."
     - name: controller_root_disk
       required: false
       schema:
         openAPIV3Schema:
           type: integer
           minimum: 1
-          example: 20
-          description: "Root disk size in GiB for control-plane nodes. OpenStack volume will be created and used instead of an ephemeral disk defined in flavor. Should be used also for the diskless flavors."
+          example: 25
+          description: "Root disk size in GiB for control-plane nodes. OpenStack volume will be created and used instead of an ephemeral disk defined in flavor. Should only be used for the diskless flavors."
     - name: worker_root_disk
       required: false
       schema:
         openAPIV3Schema:
           type: integer
           minimum: 1
-          example: 20
-          description: "Root disk size in GiB for worker nodes. OpenStack volume will be created and used instead of an ephemeral disk defined in flavor. Should be used also for the diskless flavors."
+          default: 25
+          example: 25
+          description: "Root disk size in GiB for worker nodes. OpenStack volume will be created and used instead of an ephemeral disk defined in flavor. Should be used for the diskless flavors."
     - name: yawol_flavor_id
       required: false
       schema: