Querying Metrics from Prometheus

This task shows you how to query for Istio Metrics using Prometheus. As part of this task, you will use the web-based interface for querying metric values.

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.

Querying Istio metrics

  1. Verify that the prometheus service is running in your cluster.

    In Kubernetes environments, execute the following command:

    $ kubectl -n istio-system get svc prometheus
    NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
    prometheus   ClusterIP   10.109.160.254   <none>        9090/TCP   4m
    
  2. 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
    
  3. Open the Prometheus UI.

    In Kubernetes environments, execute the following command:

    $ istioctl dashboard prometheus
    

    Click Graph to the right of Prometheus in the header.

  4. Execute a Prometheus query.

    In the “Expression” input box at the top of the web page, enter the text:

    istio_requests_total
    

    Then, click the Execute button.

The results will be similar to:

Prometheus Query Result

You can also see the query results graphically by selecting the Graph tab underneath the Execute button.

Prometheus Query Result - Graphical

Other queries to try:

  • Total count of all requests to the productpage service:

    istio_requests_total{destination_service="productpage.default.svc.cluster.local"}
    
  • Total count of all requests to v3 of the reviews service:

    istio_requests_total{destination_service="reviews.default.svc.cluster.local", destination_version="v3"}
    

    This query returns the current total count of all requests to the v3 of the reviews service.

  • Rate of requests over the past 5 minutes to all instances of the productpage service:

    rate(istio_requests_total{destination_service=~"productpage.*", response_code="200"}[5m])
    

About the Prometheus addon

The Prometheus addon is a Prometheus server that comes preconfigured to scrape Istio endpoints to collect metrics. It provides a mechanism for persistent storage and querying of Istio metrics.

For more on querying Prometheus, please read their querying docs.

Cleanup

  • Remove any istioctl processes that may still be running using control-C or:

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

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