Update docs for prometheus and grafana metrics (ray-project#29823)

1. Renamed heading and Moved customize prometheus port section to bottom.
2. Add more instructions on how to download proper binaries.
3. Add screenshot for logging in as grafana admin user

Signed-off-by: Alan Guo [email protected]
Signed-off-by: Weichen Xu <[email protected]>

doc/source/ray-observability/ray-metrics.rst

@@ -16,7 +16,9 @@ Getting Started
 
 Ray exposes its metrics in Prometheus format. This allows us to easily scrape them using Prometheus.
 
-First, `download Prometheus. <https://prometheus.io/download/>`_
+First, `download Prometheus <https://prometheus.io/download/>`_. Make sure to download the correct binary for your operating system. (Ex: darwin for mac osx)
+
+Then, unzip the the archive into a local directory using the following command.
 
 .. code-block:: bash
 
@@ -55,17 +57,6 @@ Now, you can access Ray metrics from the default Prometheus url, `http://localho
 
 See :ref:`here <multi-node-metrics>` for more information on how to set up Prometheus on a Ray Cluster.
 
-Export Metrics from Prometheus Endpoint
----------------------------------------
-
-It's also possible to expose metrics through `ray start`.
-
-.. code-block:: bash
-
-    ray start --head --metrics-export-port=8080 # Assign metrics export port on a head node.
-
-Now, you can scrape Ray's metrics using Prometheus via ``<ip>:8080``.
-
 .. _grafana:
 
 Grafana
@@ -75,9 +66,9 @@ allows you to create custom dashboards with your favorite metrics. Ray exports s
 configurations which includes a default dashboard showing some of the most valuable metrics
 for debugging ray applications.
 
-First, `download Grafana. <https://grafana.com/grafana/download>`_
+First, `download Grafana <https://grafana.com/grafana/download>`_. Follow the instructions on the download page to download the right binary for your operating system.
 
-Then run grafana using the built in configuration found in `/tmp/ray/session_latest/metrics/grafana` folder.
+Then go to to the location of the binary and run grafana using the built in configuration found in `/tmp/ray/session_latest/metrics/grafana` folder.
 
 .. code-block:: shell
 
@@ -86,7 +77,10 @@ Then run grafana using the built in configuration found in `/tmp/ray/session_lat
 Now, you can access grafana using the default grafana url, `http://localhost:3000`.
 If this is your first time, you can login with the username: `admin` and password `admin`.
 
-You can then see the default dashboard by going to dashboards -> manage -> Ray -> Default Dashboard. The same dashboard is also accessible via :ref:`Ray Dashboard <ray-dashboard>`.
+.. image:: https://raw.githubusercontent.com/ray-project/Images/master/docs/new-dashboard/grafana_login.png
+    :align: center
+
+You can then see the default dashboard by going to dashboards -> manage -> Ray -> Default Dashboard. The same metric graphs are also accessible via :ref:`Ray Dashboard <ray-dashboard>`.
 
 .. image:: https://raw.githubusercontent.com/ray-project/Images/master/docs/new-dashboard/default_grafana_dashboard.png
     :align: center
@@ -123,3 +117,15 @@ If you open this in the browser, you should see the following output:
   ray_num_requests_total{Component="core_worker",Version="3.0.0.dev0",actor_name="my_actor"} 2.0
 
 Please see :ref:`ray.util.metrics <custom-metric-api-ref>` for more details.
+
+Customize prometheus export port
+--------------------------------
+
+Ray by default provides the service discovery file, but you can directly scrape metrics from prometheus ports.
+To do that, you may want to customize the port that metrics gets exposed to a pre-defined port.
+
+.. code-block:: bash
+
+    ray start --head --metrics-export-port=8080 # Assign metrics export port on a head node.
+
+Now, you can scrape Ray's metrics using Prometheus via ``<ip>:8080``.