document kube-state-metrics configuration (#251)

Author: dgrove-oss

kube-state-metrics/README.md

@@ -0,0 +1,37 @@
+This directory contains configuration files for enabling
+[kube-state-metrics](https://github.com/kubernetes/kube-state-metrics/)
+to report metrics for AppWrappers.
+
+The file [appwrapper-ksm-cm.yaml](./appwrapper-ksm-cm.yaml) defines
+a configuration map that can be volume-mounted into the
+kube-state-metrics pod and passed via the `--custom-resource-state-config-file`
+command line argument.  For development of the AppWrapper metrics,
+you may want to add `--custom-resource-state-only=true` to the command
+line arguments to suppress generation of metrics for built-in types.
+
+The file [appwrapper-ksm-rbac.yaml](./appwrapper-ksm-rbac.yaml) defines
+a clusterrole and clusterrolebinding that add the RBACs
+needed to collect AppWrapper metrics to the `kube-state-metrics` service account.
+Alternatively, you could edit the existing kube-state-metrics clusterrole to
+add these permissions.
+
+The changes to the kube-state-metrics deployment are roughly as shown below:
+```yaml
+  ...
+    spec:
+      containers:
+      - args:
+        - --custom-resource-state-config-file=/appwrapper_ksm.yaml
+  ...
+        volumeMounts:
+        - mountPath: /appwrapper_ksm.yaml
+          name: appwrapper-ksm
+          readOnly: true
+          subPath: appwrapper_ksm.yaml
+  ...
+      volumes:
+      - configMap:
+          defaultMode: 420
+          name: appwrapper-ksm
+        name: appwrapper-ksm
+```

kube-state-metrics/metrics-cm.yaml renamed to kube-state-metrics/appwrapper-ksm-cm.yaml

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+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: kube-state-metrics-appwrapper
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: kube-state-metrics-appwrapper
+subjects:
+- kind: ServiceAccount
+  name: kube-state-metrics
+  namespace: kube-system
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: kube-state-metrics-appwrapper
+rules:
+- apiGroups:
+  - apiextensions.k8s.io
+  resources:
+  - customresourcedefinitions
+  verbs:
+  - list
+  - watch
+- apiGroups:
+  - workload.codeflare.dev
+  resources:
+  - appwrappers
+  verbs:
+  - list
+  - watch