allow overriding of deploy params by a vendor

docs/developer/vendor-overrides.md

@@ -0,0 +1,66 @@
+# Vendor overrides
+
+As a downstream consumer of `foremanctl` you might want to diverge from defaults `foremanctl` offers.
+Here's how.
+
+## Parameters
+
+If you want to override parameters, ship a playbook definition that overrides the parameter you want and add it to the `includes` of the command you want to alter.
+
+Example:
+`src/playbooks/_vendor_override/metadata.obsah.yaml`:
+```yaml
+---
+variables:
+  flavor:
+    choices:
+      - satellite
+```
+
+`src/playbooks/deploy/metadata.obsah.yaml`:
+```yaml
+…
+include:
+  …
+  - _vendor_override
+```
+
+## Features
+
+Changes to features can be done by providing a (partial) feature definition in a YAML file in `src/features.d` (probably shipped as `/usr/share/foremanctl/src/features.d`).
+
+### Adding features
+
+If you want to add a new feature, ship its definition in a file inside `src/features.d`.
+
+Example:
+```yaml
+cookies:
+  description: Delicious enterprise cookies
+  foreman:
+    plugin_name: foreman_cookies
+```
+
+### Removing features
+
+If you want to hide a previously defined feature (fully removing is not possible), set it to `internal: true` in a file inside `src/features.d`.
+
+Example:
+```yaml
+content/ostree:
+  internal: true
+```
+
+### Changing features
+
+If you want to update any part of a previously defined feature, provide the changes in a file inside `src/features.d`.
+
+Example:
+```yaml
+iop:
+  description: Lightspeed
+```
+
+## Images
+
+See [Image Management](deployment.md#image-management) in the Deployment documentation.

src/playbooks/_vendor_override/metadata.obsah.yaml

@@ -0,0 +1,5 @@
+---
+variables:
+  flavor:
+    choices:
+      - satellite

src/playbooks/deploy/metadata.obsah.yaml

@@ -26,3 +26,4 @@ variables:
 include:
   - _flavor_features
   - _flavors/katello
+  - _vendor_override