chapter-13

Chapter 13 - Observing Reactive and Event-Driven Architectures

Pre-requisites

• Helm installed

Kubernetes cluster

Have a Kubernetes cluster running, or start Minikube:

minikube start --memory=4096

Install Kafka

Install Strimzi

kubectl create ns strimzi
kubectl create ns kafka

helm repo add strimzi https://strimzi.io/charts
helm install strimzi strimzi/strimzi-kafka-operator -n strimzi --set watchNamespaces={kafka} --wait --timeout 300s

When Strimzi is finished installing, we will see the operator in a running state:

kubectl get pods -n strimzi
NAME                                        READY   STATUS    RESTARTS   AGE
strimzi-cluster-operator-58fcdbfc8f-mjdxg   1/1     Running   0          46s

Create Kafka cluster

With the operator running, we can now create a Kafka cluster!

kubectl apply -f deploy/kafka/kafka-cluster.yaml -n kafka

We can verify successful installation of the cluster with:

kubectl get pods -n kafka
NAME                                          READY   STATUS    RESTARTS   AGE
my-cluster-entity-operator-765f64f4fd-2t8mk   3/3     Running   0          90s
my-cluster-kafka-0                            1/1     Running   0          113s
my-cluster-zookeeper-0                        1/1     Running   0          2m12s

Create Topics

kubectl apply -f deploy/kafka/ticks.yaml
kubectl apply -f deploy/kafka/processed.yaml

Install Jaeger - Only for Distributed Tracing

Install Jaeger All In One

kubectl create ns jaeger

kubectl apply -f deploy/jaeger/jaeger-simplest.yaml -n jaeger

This is not the recommended way to install Jaeger for production usage, but it's sufficient for our needs.

We can verify successful installation with:

kubectl get pods -n jaeger
NAME                      READY   STATUS    RESTARTS   AGE
jaeger-64ffd7f658-vbwwg   1/1     Running   0          5s

Update application

Ensure each of the services has the following dependency present in pom.xml:

<dependency>
  <groupId>io.quarkus</groupId>
  <artifactId>quarkus-opentelemetry-exporter-jaeger</artifactId>
</dependency>

Verify the configuration for the jaeger endpoint is uncommented in application.properties:

quarkus.opentelemetry.tracer.exporter.jaeger.endpoint=http://simplest-collector.jaeger:14250

Application deployment

If using Minikube, run:

eval $(minikube -p minikube docker-env)

Build and deploy the services:

cd viewer
mvn verify -Dquarkus.kubernetes.deploy=true
cd ..
# To deploy the processor with nacking for health check verification
cd processor-health
# To deploy the processor without nacking
cd processor
mvn verify -Dquarkus.kubernetes.deploy=true
cd ..
cd ticker
mvn verify -Dquarkus.kubernetes.deploy=true
cd ..

Verify they're all working with kubectl get pods.

Redeploy updated code

mvn verify -Dquarkus.container-image.build=true

Using the application

With the application started, open a browser window to the SSE endpoint to see the results:

export VIEWER_URL=`minikube service --url observability-viewer`
echo "Open url: ${VIEWER_URL}"