4.3. Using Jaeger distributed tracing

Procedure

1. Create and apply a Jaeger custom resource (CR) that contains the following:

   Jaeger CR

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

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

   Tracing YAML example for Serving

   apiVersion: operator.knative.dev/v1beta1
   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 are 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 CR 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.

3. Enable tracing for Knative Eventing by editing the KnativeEventing CR:

   Tracing YAML example for Eventing

   apiVersion: operator.knative.dev/v1beta1
   kind: KnativeEventing
   metadata:
     name: knative-eventing
     namespace: knative-eventing
   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 are sampled.

   2

   Set backend to zipkin.

   3

   Point the zipkin-endpoint to your jaeger-collector service endpoint. To get this endpoint, substitute the namespace where the Jaeger CR 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 -n default

   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.