Monitoring Doc Fixups

monitoring/api/v3/README.md

@@ -14,28 +14,52 @@ value to it.
 
 Go to the [Google Cloud Console](https://console.cloud.google.com).
 
-* Go to API Manager -> Credentials
-* Click 'New Credentials', and create a Service Account or [click  here](https://console.cloud.google
-.com/project/_/apiui/credential/serviceaccount)
- Download the JSON for this service account, and set the `GOOGLE_APPLICATION_CREDENTIALS`
- environment variable to point to the file containing the JSON credentials.
-
-
-    export GOOGLE_APPLICATION_CREDENTIALS=~/Downloads/<project-id>-0123456789abcdef.json
-
 
 # Set Up Your Local Dev Environment
 To install, run the following commands. If you want to use  [virtualenv](https://virtualenv.readthedocs.org/en/latest/)
 (recommended), run the commands within a virtualenv.
 
     * pip install -r requirements.txt
 
-To run locally:
+Create local credentials by running the following command and following the oauth2 flow:
+
+    gcloud beta auth application-default login
+
+To run:
 
     python list_resources.py --project_id=<YOUR-PROJECT-ID>
     python custom_metric.py --project_id=<YOUR-PROJECT-ID
 
 
+## Running on GCE, GAE, or other environments
+
+On Google App Engine, the credentials should be found automatically.
+
+On Google Compute Engine, the credentials should be found automatically, but require that
+you create the instance with the correct scopes. 
+
+    gcloud compute instances create --scopes="https://www.googleapis.com/auth/cloud-platform,https://www.googleapis.com/auth/compute,https://www.googleapis.com/auth/compute.readonly" test-instance
+
+If you did not create the instance with the right scopes, you can still upload a JSON service 
+account and set GOOGLE_APPLICATION_CREDENTIALS as described below.
+
+
+## Using a Service Account
+
+In non-Google Cloud environments, GCE instances created without the correct scopes, or local
+workstations if the `gcloud beta auth application-default login` command fails, use a Service 
+Account by doing the following:
+
+* Go to API Manager -> Credentials
+* Click 'New Credentials', and create a Service Account or [click  here](https://console.cloud.google
+.com/project/_/apiui/credential/serviceaccount)
+ Download the JSON for this service account, and set the `GOOGLE_APPLICATION_CREDENTIALS`
+ environment variable to point to the file containing the JSON credentials.
+
+
+    export GOOGLE_APPLICATION_CREDENTIALS=~/Downloads/<project-id>-0123456789abcdef.json
+
+
 ## Contributing changes
 
 * See [CONTRIBUTING.md](CONTRIBUTING.md)