Chapter 8. Tracing requests using Jaeger

Procedure

1. Create and apply a Jaeger custom resource YAML file that contains the following sample YAML:

   Jaeger custom resource YAML

   apiVersion: jaegertracing.io/v1
   kind: Jaeger
   metadata:
     name: jaeger
     namespace: default

2. Enable tracing for Knative Serving, by editing the KnativeServing resource and adding a YAML configuration for tracing.

   Tracing YAML example

   apiVersion: operator.knative.dev/v1alpha1
   kind: KnativeServing
   metadata:
     name: knative-serving
     namespace: knative-serving
   spec:
     config:
       tracing:
         sample-rate: "0.1" 1
         backend: zipkin 2
         zipkin-endpoint: http://jaeger-collector.default.svc.cluster.local:9411/api/v2/spans 3
         debug: "false" 4

   1

   The sample-rate defines sampling probability. Using sample-rate: "0.1" means that 1 in 10 traces will be sampled.

   2

   backend must be set to zipkin.

   3

   The zipkin-endpoint must point to your jaeger-collector service endpoint. To get this endpoint, substitute the namespace where the Jaeger custom resource is applied.

   4

   Debugging should be set to false. Enabling debug mode by setting debug: "true" allows all spans to be sent to the server, bypassing sampling.

1. Get the jaeger route’s hostname by entering the following command:

   $ oc get route jaeger

   Example output

   NAME     HOST/PORT                         PATH   SERVICES       PORT    TERMINATION   WILDCARD
   jaeger   jaeger-default.apps.example.com          jaeger-query   <all>   reencrypt     None

2. Open the endpoint address in your browser to view the console.