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JCConf Taiwan 2021 Access Kubernetes API in Java Matt Ho Access Kubernetes API in Java

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Hi, I'm Matt https://github.com/shihyuho methodho@gmail.com @SoftLeader Access Kubernetes API in Java

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Requirements Some experience with Java and Spring. Basic understanding of Kubernetes. YAML language. Access Kubernetes API in Java

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你爲什麼會需要去跟 Kubernetes 互動? Access Kubernetes API in Java

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Kubernetes Architecture Access Kubernetes API in Java

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Kubernetes Architecture Access Kubernetes API in Java

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環境準備 Local Kubernetes cluster 推薦: docker + minikube # Start the cluster $ minikube start # Configure environment to use minikube’s Docker daemon $ eval $(minikube docker-env) # Halt the cluster $ minikube stop Access Kubernetes API in Java

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環境準備 A simple web app w/ Spring Boot $ curl https://start.spring.io/starter.zip \ -d dependencies=web,lombok,devtools \ -d bootVersion=2.5.7 \ -o demo.zip Access Kubernetes API in Java

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環境準備 Add the following dependency to your pom.xml file: io.fabric8 kubernetes-client 5.10.1 org.springdoc springdoc-openapi-ui 1.5.12 Access Kubernetes API in Java

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Kubernetes Java Client Officially-supported - kubernetes-client/java Community-maintained - fabric8io/kubernetes-client Access Kubernetes API in Java

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起手式 try (var client = new DefaultKubernetesClient()) { client.{apiGroup}.{apiVersion}.{resource}.{verb}... } Access Kubernetes API in Java

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kubectl get pod -n default kubectl get service -A kubectl get deploy -l my=label kubectl get cronjob myjob Access Kubernetes API in Java

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A Hello Pod apiVersion: v1 kind: Pod metadata: name: hello spec: containers: - name: hello image: busybox imagePullPolicy: IfNotPresent command: ["sh", "-c", "echo Hello JCConf Taiwan; sleep 2"] restartPolicy: Never Access Kubernetes API in Java

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Builder Pattern new {Resource}Builder() .withNew{FieldObject} .with{Field}(...) .with{Field}(...) .end{FieldObject} .build(); Access Kubernetes API in Java

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Packing Image mvn compile com.google.cloud.tools:jib-maven-plugin:3.1.4:dockerBuild -Djib.to.image=demo:1.0.0 # mvn spring-boot:build-image -Dspring-boot.build-image.imageName=demo:1.0.0 Access Kubernetes API in Java

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Deploy apiVersion: apps/v1 kind: Deployment metadata: name: demo spec: selector: matchLabels: app: demo template: metadata: labels: app: demo spec: containers: - name: demo image: demo:1.0.0 Access Kubernetes API in Java

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Kubernetes RBAC Access Kubernetes API in Java

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Kubernetes RBAC Access Kubernetes API in Java

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Kubernetes RBAC Access Kubernetes API in Java

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apiVersion: v1 kind: ServiceAccount metadata: name: demo namespace: default --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: demo rules: - apiGroups: [ "" ] resources: [ "pods" ] verbs: [ "get", "list", "watch", "create", "update", "patch", "delete" ] - apiGroups: [ "" ] resources: [ "events" ] verbs: [ "list" ] --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: demo roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: demo subjects: - kind: ServiceAccount name: demo namespace: default Access Kubernetes API in Java

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Recap Basic understanding of Kubernetes API. How to access Kubernetes API in Java. How to configure access control to the app. Demo code. Access Kubernetes API in Java

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Thank you Access Kubernetes API in Java