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.

    Note: $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/dotviz in your web browser.

    The results will look similar to:

Example Servicegraph
Example Servicegraph

About the Servicegraph Add-on

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

  • /graph which provides a JSON serialization of the servicegraph
  • /dotgraph which provides a dot serialization of the servicegraph
  • /dotviz which provides a visual representation of the servicegraph

All endpoints take an optional argument of time_horizon, which controls the timespan to consider for graph generation.

All endpoints also take an optional argument of filter_empty=true, which will restrict the nodes and edges shown to only those that reflect non-zero traffic levels during the specified time_horizon.

The Servicegraph example is built on top of Prometheus queries.

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.