Update Grafana Demo README.

Summary: updating Grafana Demo to have the full deployment instructions for someone outside of Pixie.

Test Plan: N/A

Reviewers: vihang, michelle

Reviewed By: michelle

Signed-off-by: Taras Priadka <tpriadka@pixielabs.ai>

Differential Revision: https://phab.corp.pixielabs.ai/D12001

GitOrigin-RevId: 8b76f66

Author: TarasPriadka

k8s/grafana_demo/README.md

@@ -1,16 +1,29 @@
 # Grafana Plugin Demo
 
-This demo is intended to display a sample use of Pixie Datasource Plugin for Grafana. This folder contains manifests to deploy and configure a sample grafana application which displays information about a sample cluster.
+This demo is intended to display a sample use of Pixie Datasource Plugin for Grafana. This folder contains manifests to deploy and configure a sample Grafana application which displays information about a sample cluster.
 
 ## Deploy Grafana Demo Application
 
+1. Define your secret file. Example:
+```
+apiVersion: v1
+kind: Secret
+metadata:
+    name: grafana-demo-secret
+type: Opaque
+stringData:
+    PIXIE_API_KEY: api_key
+```
+2. Deploy demo application:
 ```
   kubectl apply -f PATH_TO_SECRET/grafana_plugin_secret.yaml
-  kubectl apply -f pixielabs/demos/grafana-demo/
+  kubectl apply -f PATH_TO_PIXIE_REPO/k8s/grafana_demo
 ```
-
+Note:
+Since the the ingress manifests are configured to work with Pixie GCP DNS, you will want to configure `grafana-ingress.yaml` with your DNS configurations.
+If you don't want to use ingress configurations, you may delete `grafana-ingress.yaml`, and change `grafana-service.yaml` to change service type to `LoadBalancer`.
 ## Delete Grafana Demo Application
 
 ```
-  kubectl delete -f pixielabs/demos/grafana-demo/ --ignore-not-found=true
+  kubectl delete -f PATH_TO_PIXIE_REPO/k8s/grafana_demo --ignore-not-found=true
 ```