Tracing requests using Jaeger - Monitor | Serverless

Configuring Jaeger for use with OpenShift Serverless

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

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.

Configuring Jaeger for use with OpenShift Serverless

You can use the following procedure to set up Jaeger for use with OpenShift Serverless.

Prerequisites

You have access to an OpenShift Dedicated account with cluster or dedicated administrator access.
You have installed the OpenShift Serverless Operator and Knative Serving.
You have installed the Jaeger Operator.
Install the OpenShift CLI (oc).
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Dedicated.

Procedure

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

Enable tracing for Knative Serving, by editing the KnativeServing CR 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 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.

Verification

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

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

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