Add raw SeedImage documentation (#261)

Add new fields to SeedImage reference:

* Type
* TargetPlatform
* BuildContainer

Signed-off-by: Fredrik Lönnegren <[email protected]>

docs/seedimage-reference.md

@@ -9,14 +9,20 @@ title: ''
 
 # SeedImage reference
 
-A `SeedImage` resource allows to build an ISO that can be used to install Elemental onto a node.  
-It requires a `baseImage`, i.e., a URL to an Elemental installation ISO, and a `registrationRef` reference to a `MachineRegistration` resource, from which the registration part of the Elemental configuration is extracted and injected in the ISO to produce the final *seed image*.  
-It is also possible to inject ISO customizations in the `cloud-config` field.
+A `SeedImage` resource allows to build an installation media that can be used to install Elemental onto a node.
+It requires a `baseImage`, i.e., a URL to an Elemental installation ISO or node container image, and a `registrationRef` reference to a `MachineRegistration` resource, from which the registration part of the Elemental configuration is extracted and injected in the media to produce the final *seed image*.
+It is also possible to inject customizations in the `cloud-config` field.
 
 Once the seed image is ready, the download URL is shared in the `.status.downloadURL` field.
-It stays available for download for `cleanupAfterMinutes` minutes (default is `60`, 1 hour), after which it is deleted.  
+It stays available for download for `cleanupAfterMinutes` minutes (default is `60`, 1 hour), after which it is deleted.
 Setting `retriggerBuild` to `true` retriggers the seed image build process while setting `cleanupAfterMinutes` to `0` keeps the seed image around till the `SeedImage` resource is deleted.
 
+The `SeedImage` resource also has a `type` field which can be set to either `iso`, to build an ISO, or `raw` to build a raw disk image. Raw disk images can be copied directly to the target drive and on first boot will automatically boot into a recovery partition to expand the drive to use the available disk space and register the node, after which it will reboot the same way as for the ISO installation.
+
+If no `BuildContainer` is specified for the seed-image it will be automatically filled in based on default values and `type`.
+
+Building a SeedImage for a different platform is accomplished using the `targetPlatform` field. The platform is specified using `os/arch`, for example (`linux/amd64` or `linux/arm64`). By default the image will be built for the same platform that the operator is hosted on.
+
 :::warning seed images may fill up local storage
 The seed images are kept on the node's local storage: pay attention to the number of `SeedImage` resources you start concurrently and to the ones you may leave around with the auto-cleanup feature disabled (`cleanupAfterMinutes` = `0`) as you may exhaust the storage on your cluster nodes.
 :::
@@ -36,7 +42,15 @@ The `SeedImage` resource tracks the seed image build process through two status
     name: ...
     namespace: ...
   spec:
+    type: ...
     baseImage: ...
+    targetPlatform: ...
+    buildContainer:
+      name: ...
+      image: ...
+      command: [...]
+      args: [...]
+      imagePullPolicy: ...
     cloud-config: ...
     registrationRef:
       name: ...

examples/quickstart/seedimage.yaml

@@ -4,6 +4,7 @@ metadata:
   name: fire-img
   namespace: fleet-default
 spec:
+  type: iso
   baseImage: registry.suse.com/rancher/elemental-teal-iso/5.4:1.2.2
   registrationRef:
     apiVersion: elemental.cattle.io/v1beta1