Merge pull request #230 from external-secrets/docs/deprecation-policy

docs: add deprecation policy

docs/deprecation-policy.md

@@ -0,0 +1,35 @@
+# Deprecation Policy
+
+We follow the [Kubernetes Deprecation Policy](https://kubernetes.io/docs/reference/using-api/deprecation-policy/) and [API Versioning Scheme](https://kubernetes.io/docs/reference/using-api/#api-versioning): alpha, beta, GA.
+
+The project is currently in `alpha` state. We track `beta` progress in [this GitHub Project](https://github.com/external-secrets/external-secrets/projects/3). Please try the `alpha` and `beta` features and provide feedback. After the features exit beta, it may not be practical to make more changes.
+
+* alpha
+    * The support for a feature may be dropped at any time without notice.
+    * The API may change in incompatible ways in a later software release without notice.
+    * The software is recommended for use only in short-lived testing clusters, due to increased risk of bugs and lack of long-term support.
+
+* beta
+    * The software is well tested. Enabling a feature is considered safe. Features are enabled by default.
+    * The support for a feature will not be dropped, though the details may change.
+    * The schema and/or semantics of objects may change in incompatible ways in a subsequent beta or stable release. When this happens, migration instructions are provided. Schema changes may require deleting, editing, and re-creating API objects. The editing process may not be straightforward. The migration may require downtime for applications that rely on the feature.
+    * The software is not recommended for production uses. Subsequent releases may introduce incompatible changes. If you have multiple clusters which can be upgraded independently, you may be able to relax this restriction.
+* GA
+    * The stable versions of features appear in released software for many subsequent versions.
+    * Use it in production ;)
+
+## API Surface
+
+We define the following scope that is covered by our deprecation policy. We follow the [9 Rules of the Kuberenetes Deprecation Policy](https://kubernetes.io/docs/reference/using-api/deprecation-policy/).
+
+### Scope
+* API Objects and fields: `.Spec`, `.Status` and `.Status.Conditions[]`
+* Enums and constant values
+* Controller Configuration: CLI flags & environment variables
+* Metrics as defined in the [Kubernetes docs](https://kubernetes.io/docs/reference/using-api/deprecation-policy/#deprecating-a-metric)
+* a feature or specific behavior:
+    * `ExternalSecret` [update mechanics](http://localhost:8000/api-externalsecret/#update-behavior)
+
+### Non-Scope
+We do not provide stability guarantee for **source code imports**. The Interfaces and the behavior will change in a unexpected and backwards-incompatible way. However,
+The maintained helm chart is not part of this deprecation policy.

hack/api-docs/mkdocs.yml

@@ -48,3 +48,4 @@ nav:
     - Developer guide: contributing-devguide.md
     - Contributing Process: contributing-process.md
     - Code of Conduct: contributing-coc.md
+  - Deprecation Policy: deprecation-policy.md