Using Jaeger with OpenShift Serverless allows you to enable distributed tracing for your serverless applications on Azure Red Hat OpenShift.

Distributed tracing records the path of a request through the various services that make up an application.

It is used to tie information about different units of work together, to understand a whole chain of events in a distributed transaction. The units of work might be executed in different processes or hosts.

Developers can visualize call flows in large architectures with distributed tracing. which is useful for understanding serialization, parallelism, and sources of latency.

For more information about Jaeger, see Jaeger architecture and Installing Jaeger.

Configuring Jaeger for use with OpenShift Serverless

Prerequisites

To configure Jaeger for use with OpenShift Serverless, you will need:

  • Cluster administrator permissions on an Azure Red Hat OpenShift cluster.

  • A current installation of OpenShift Serverless Operator and Knative Serving.

  • A current installation of the Jaeger Operator.

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.
Verification steps

Access the Jaeger web console to see tracing data. You can access the Jaeger web console by using the jaeger route.

  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.