Improve the Kubernetes plugin documentation

- Add the `objectTypes` config
- Add the access needed to fetch pod metrics in the RBAC chapter

Signed-off-by: Mengnan Gong <namco1992@gmail.com>

.github/vale/Vocab/Backstage/accept.txt

@@ -70,6 +70,7 @@ cron
 cronjobs
 crontab
 css
+daemonsets
 Datadog
 dataflow
 dayjs
@@ -177,6 +178,7 @@ learnings
 Leasot
 lerna
 Lerna
+limitranges
 LocalStack
 lockdown
 lockfile

docs/features/kubernetes/configuration.md

@@ -402,6 +402,41 @@ view the Kubernetes API docs for your Kubernetes version (e.g.
 [API Groups for v1.22](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.22/#-strong-api-groups-strong-)
 )
 
+### `objectTypes` (optional)
+
+Overrides for the Kubernetes object types fetched from the cluster. The default object types are:
+
+- pods
+- services
+- configmaps
+- limitranges
+- deployments
+- replicasets
+- horizontalpodautoscalers
+- jobs
+- cronjobs
+- ingresses
+- statefulsets
+- daemonsets
+
+You may use this config to override the default object types if you only want a subset of
+the default ones. However, it's currently not supported to fetch object types other
+than the ones specified in the default types.
+
+Example:
+
+```yaml
+---
+kubernetes:
+  objectTypes:
+    - 'configmaps'
+    - 'deployments'
+    - 'limitranges'
+    - 'pods'
+    - 'services'
+    - 'statefulsets'
+```
+
 ### Role Based Access Control
 
 The current RBAC permissions required are read-only cluster wide, the below
@@ -441,6 +476,13 @@ rules:
       - get
       - list
       - watch
+  - apiGroups:
+      - metrics.k8s.io
+    resources:
+      - pods
+    verbs:
+      - get
+      - list
 ```
 
 ## Surfacing your Kubernetes components as part of an entity