Generating a Service Graph

This task shows you how to generate a graph of services within an Istio mesh. As part of this task, you will install the Servicegraph addon and use the web-based interface for viewing service graph of the service mesh.

The Bookinfo sample application is used as the example application throughout this task.

Before you begin

• Install Istio in your cluster and deploy an application.

• Install the Prometheus add-on. Directions for install of this add-on are supplied as part of the Querying Metrics Task.

  Use of the Prometheus add-on is required for the service graph.

Generating a Service Graph

1. To view a graphical representation of your service mesh, install the Servicegraph add-on.

   In Kubernetes environments, execute the following command:

   kubectl apply -f install/kubernetes/addons/servicegraph.yaml
   

2. Verify that the service is running in your cluster.

   In Kubernetes environments, execute the following command:

   kubectl -n istio-system get svc servicegraph
   

   The output will be similar to:

   NAME           CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
   servicegraph   10.59.253.165   <none>        8088/TCP   30s
   

3. Send traffic to the mesh.

   For the Bookinfo sample, visit http://$GATEWAY_URL/productpage in your web browser or issue the following command:

   curl http://$GATEWAY_URL/productpage
   

   Refresh the page a few times (or send the command a few times) to generate a small amount of traffic.

   $GATEWAY_URL is the value set in the Bookinfo guide.

4. Open the Servicegraph UI.

   In Kubernetes environments, execute the following command:

   kubectl -n istio-system port-forward $(kubectl -n istio-system get pod -l app=servicegraph -o jsonpath='{.items[0].metadata.name}') 8088:8088 &
   

   Visit http://localhost:8088/force/forcegraph.html in your web browser. Try clicking on a service to see details on the service. Real time traffic data is shown in a panel below.

   The results will look similar to:

1. Experiment with Query Parameters

   Visit http://localhost:8088/force/forcegraph.html?time_horizon=15s&filter_empty=true in your web browser. Note the query parameters provided.

   filter_empty=true will only show services that are currently receiving traffic within the time horizon.

   time_horizon=15s affects the filter above, and also affects the reported traffic information when clicking on a service. The traffic information will be aggregated over the specified time horizon.

   The default behavior is to not filter empty services, and use a time horizon of 5 minutes.

About the Servicegraph Add-on

The Servicegraph service provides endpoints for generating and visualizing a graph of services within a mesh. It exposes the following endpoints:

• /force/forcegraph.html As explored above, this is an interactive D3.js visualization.

• /dotviz is a static Graphviz visualization.

• /dotgraph provides a DOT serialization.

• /d3graph provides a JSON serialization for D3 visualization.

• /graph provides a generic JSON serialization.

All endpoints take the query parameters explored above.

The Servicegraph example is built on top of Prometheus queries and depends on the standard Istio metric configuration.

Cleanup

• In Kubernetes environments, execute the following command to remove the Servicegraph add-on:

   kubectl delete -f install/kubernetes/addons/servicegraph.yaml
  

• If you are not planning to explore any follow-on tasks, refer to the Bookinfo cleanup instructions to shutdown the application.