Building a Kubernetes Operator in Quarkus

D E M 3 5 - S Building a Kubernetes Operator in Quarkus

Fabian Lange VP of Engineering Instana

Kubernetes? Container orchestration system

An Operator? Kubernetes software extension to manage applications and its components

Quarkus? Java framework designed for Kubernetes

mvn \

io.quarkus:quarkus-maven-plugin:0.19.1:create \

-DprojectGroupId=com.instana \

-DprojectArtifactId=operator-example \

-DclassName="com.instana.operator.HelloResource" \

-Dpath="/hello"

mvn \

quarkus:add-extension \

-Dextensions=quarkus-kubernetes-client Creating a Kubernetes Client package com.instana.operator; public class ClientProducer {

@Produces @Singleton KubernetesClient makeDefaultK8sClient(@Named("namespace") String namespace) { return new DefaultKubernetesClient().inNamespace(namespace); }

@Produces @Singleton @Named("namespace") String findMyNamespace() throws IOException { return new String(Files.readAllBytes( Paths.get("/var/run/secrets/kubernetes.io/serviceaccount/namespace"))); } } Listing and Watching Pods

package com.instana.operator; public class PodLister {

@Inject KubernetesClient defaultClient;

void onStartup(@Observes StartupEvent e) { defaultClient.pods().list().getItems().stream() .map(PodPrinter::toString) .forEach(System.out::println);

defaultClient.pods().watch(new Watcher() {

public void eventReceived(Action action, Pod pod) { System.out.println(action + " on " + PodPrinter.toString(pod)); }

}); } } Building and Running

mvn \

clean package -DskipTests && \

docker build -f src/main/docker/Dockerfile.jvm -t instana/demo-operator:1 . && \

kind load docker-image instana/demo-operator:1 kubectl run --image=nginx --restart=Never nginx1 kubectl apply -f operator.yaml kubectl run --image=nginx --restart=Never nginx2

NAME READY STATUS RESTARTS AGE nginx1 1/1 Running 0 23s operator-example-6fb74d98c5-5zzj9 1/1 Running 0 19s nginx2 1/1 Running 0 14s Operator Output

exec java -Dquarkus.http.host=0.0.0.0 - Djava.util.logging.manager=org.jboss.logmanager.LogManager -javaagent:/opt/agent-bond/agent- bond.jar=jmx_exporter{{9779:/opt/agent-bond/jmx_exporter_config.yml}} -XX:+UseParallelGC - XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90 -XX:MinHeapFreeRatio=20 - XX:MaxHeapFreeRatio=40 -XX:+ExitOnOutOfMemoryError -cp . -jar /deployments/app.jar

Pod nginx1 version 3143

Pod operator-example-6989bcf5f8-j4d2d version 3457

2019-10-14 14:35:02,320 INFO [io.quarkus] (main) Quarkus 0.19.1 started in 1.866s. Listening on: http://[::]:8080

2019-10-14 14:35:02,322 INFO [io.quarkus] (main) Installed features: [cdi, kubernetesclient, resteasy]

ADDED on Pod nginx2 version 4512

MODIFIED on Pod nginx2 version 4513

MODIFIED on Pod nginx2 version 4514