capping funciton now returns which zones were sucessfully capped and which zones could not be capped. This information is now returned to the caller of the HTTP api.

rapl-daemon/README.md

@@ -11,3 +11,29 @@ on all worker nodes.
   --data '{"percentage":75}' \
   http://localhost:9090/powercap
  ```
+
+### Payload
+
+```json
+{
+    "percentage":75
+}
+```
+
+### Response
+
+The daemon will respond with a json payload containing zones that were
+successfully capped as well as the zones that were not capped.
+
+```json
+{
+    "cappedZones": null,
+    "failedZones": [
+        "intel-rapl:0",
+        "intel-rapl:1"
+    ],
+    "error": "some zones were not able to be powercapped"
+}
+```
+
+Field error will not exist if failed zones is empty.