Downloaded 11 times
![SAMPLE
DOCKERFILE
FROM maven:3.5-jdk-8 as BUILD
COPY . /usr/src/app
WORKDIR /usr/src/app
RUN mvn package
FROM openjdk:8-jre
EXPOSE 8080 5005
COPY --from=BUILD /usr/src/app/target /opt/target
WORKDIR /opt/target
ENV _JAVA_OPTIONS '-
agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005'
CMD ["java", "-jar", "helloworld.war"]](https://image.slidesharecdn.com/kubernetesforjavadevelopers-201022081059/75/Kubernetes-for-Java-developers-10-2048.jpg)
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Similar to Kubernetes for Java developers
Kubernetes for Java developers
- 1. KUBERNETES FOR JAVADEVELOPERS ROBERT BARR
- 2. ABOUT ME Java developerand engineering manager since Java 1.1.7 Engineering Lead for DevOps and Development Practices Group Head of Development and Data Grid for Infrastructure Engineering Group Co-organiser for the Docklands London Java Community
- 3. ABOUT ME Java developerand engineering manager since Java 1.1.7 Engineering Lead for DevOps and Development Practices Group Head of Development and Data Grid for Infrastructure Engineering Group Co-organiser for the Docklands London Java Community
- 4. AGENDA Quarkus, Micronautand Spring Boot Docker recap Why Kubernetes? Kubernetes architectureand concepts Running Kuberneteslocally Related Kubernetesconcepts Deployment pipelines
- 5. SAMPLE APPLICATION @RestController public class HelloWorldController{ @RequestMapping("/hello") public String sayHello() { return "hi mum"; } } https://github.com/runesmith2013/k8s4j.git
- 6. QUARKUS VS MICRONAUTVS SPRING BOOT Quarkus is a “supersonic subatomic Java”. It is a Kubernetes-native Java stack designed for OpenJDK HotSpot and GraalVM and includes the best Java libraries and standards. One of the pros of Quarkus is its speedy start-up time. Micronaut is a cloud-native JVM-based polyglot full-stack framework for building microservices and serverless applications. It features low memory consumption, no matter the size of your codebase. Spring Boot is an open source Java framework that makes it easy to create stand-alone production-grade Spring applications and microservices with embedded Tomcat, Jetty, or Undertow. Spring Boot apps require little configuration so they can “just run”. Project Leyden: New OpenJDK project to address Java start up time Static application binaries with faster startup and lower memory. Once approved and completed, this would enable developers to compile Java code (just-in-time) to native applications (ahead-of-time), offering capabilities like GraalVM's native mode.
- 7. QUARKUS VS MICRONAUTVS SPRING BOOT https://jaxenter.com/micronaut-speed-test-170870.html Source: https://jaxenter.com/micronaut-speed-test-170870.html
- 8. Packages applications withtheir dependencies into a portable, lightweightcontainer This container can run locally, on premise or on cloud hosted infrastructure such as AWS Elastic Container Service Docker solves the issue of environmental differences between Prod, UAT and DEV
- 9. DOCKER TERMINOLOGY DockerDaemon – runs on your host and listens for Docker API requests. Manages containers and images Docker Image – base for running an application Docker container - running instance of a Docker image Dockerfile – script defining how to construct a Docker image Docker hub - online repo for storing Docker images
- 10. SAMPLE DOCKERFILE FROM maven:3.5-jdk-8 asBUILD COPY . /usr/src/app WORKDIR /usr/src/app RUN mvn package FROM openjdk:8-jre EXPOSE 8080 5005 COPY --from=BUILD /usr/src/app/target /opt/target WORKDIR /opt/target ENV _JAVA_OPTIONS '- agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005' CMD ["java", "-jar", "helloworld.war"]
- 11. COMMON DOCKER COMMANDS dockerimage build –t tag/tag:version . Communicates with the docker daemon to construct an image based on the dockerfile. docker image ls Shows the images stored in the local repo docker run –p 8080:8080 –d imagename instantiate and run a container from an image, exposing ports and running in detached mode docker push myrepo/myimage:2.0 Push an image to a registry https://www.docker.com/sites/default/files/d8/2019-09/docker-cheat-sheet.pdf
- 12. DOCKER AND MAVEN:SPOTIFY PLUGIN <plugin> <groupId>com.spotify</groupId> <artifactId>dockerfile-maven-plugin</artifactId> <version>${dockerfile-maven-version}</version> <executions> <execution> <id>default</id> <goals> <goal>build</goal> <goal>push</goal> </goals> </execution> </executions> <configuration> <repository>spotify/foobar</repository> <tag>${project.version}</tag> <buildArgs> <JAR_FILE>${project.build.finalName}.jar</JAR_FILE> </buildArgs> </configuration> * requires docker * requires a dockerfile * mvn build creates an image * mvn deploy pushes to repo Project is MATURE and not adding new features
- 13. DOCKER AND MAVEN:JIB PLUGIN <plugin> <groupId>com.google.cloud.tools</groupId> <artifactId>jib-maven-plugin</artifactId> <version>2.5.0</version> <configuration> <to> <image>${image.path}</image> </to> </configuration> </plugin> * does not require docker * does not require a Dockerfile * opinionated default options * separates app into layers – classes, resources, dependencies * only builds changed layers
- 14. WHY KUBERNETES? Kubernetes isopen source software for deploying, scaling and managing containerized applications. As an orchestrator,it handles the work of scheduling containers on a cluster and manages the workloads to ensure they run as intended.
- 15. WHY KUBERNETES? Portability Kubernetes offersportability, and faster, simpler deployment times. Scalability With Kubernetes ability to run containers on one or more public cloud environments, in virtual machines, or on bare metal means that it can be deployed almost anywhere and scale to any extent.
- 16. WHY KUBERNETES? High Availability Kubernetesaddresses high availability at both the application and the infrastructure level. OpenSource Since Kubernetes is open source, you can take advantage of the vast ecosystem of other open source tools designed specifically to work with Kubernetes without the lock-in of a closed/proprietary system.
- 17. WHY KUBERNETES? Proven, andBattle Tested A huge ecosystem of developers and tools with 5,608 GitHub repositories and counting means that you won’t be forging ahead into new territory without help. Kubernetes 101 Architecture Kubernetes can manage rolling updates, adapts to additional workloads by auto scaling nodes to increase capacity and can self-heal in the case of a pod meltdown.
- 18. KUBERNETES CONTROL PLANE ETCD EtcdStorage Is an open-source key-value data store Stores configuration data of the cluster’s state.
- 19. KUBERNETES CONTROL PLANE ETCD API Server Kube-API-Server– The API server manages requests from the worker nodes, receives REST requests for modifications, and serves as a front- end to control cluster.
- 20. KUBERNETES CONTROL PLANE ETCD API Server Scheduler Kube-scheduler– Schedules the pods on nodes based on resource utilization and decides where services are deployed: Quality of Service requirements, hardware, software, policy constraints, affinity and anti-affinity requirements
- 21. KUBERNETES CONTROL PLANE ETCD API Server Scheduler Controller manager Kube-controller-manager– A set of distinct controller processes to regulate the shared state of the cluster and perform routine tasks. When there is a change to a service, the controller recognizes the change and initiates an update to bring the cluster up to the desired state. Includes the replication controller, endpoints controller and namespace controller
- 22. KUBERNETES CONTROL PLANE ETCD API Server Scheduler Controller manager Cloud controller Cloudcontroller manager Embeds cloud specific control logic
- 23. KUBERNETES CONTROL PLANE ETCD API Server Scheduler Controller manager Cloud controller Add Ons AddOns Extends the functionality of Kubernetes. DNS is a recommended add-on, which provides name resolution for objects deployed in Kubernetes
- 24. KUBERNETES WORKER Kubelet Kubelet Primary nodeagent that runs on each node Communicates with master and ensures containers are running and healthy
- 25. KUBERNETES WORKER Kubelet Kube-proxy Network proxyrunning on each node Provides K8s networking services Kube-proxy
- 26. KUBERNETES FLOW kubectl ControlPlane Data Plane kubectl apply –f resource.yaml
- 27. KUBERNETES CONCEPTS Containers Typically Docker containers,but Kubernetes also supports a variety of other container types Pods A pod is the basic building block for Kubernetes. Pods are generally collections of related containers, but a pod may also only have one container. A pod shares network/storage and a specification for how to run the containers.
- 28. KUBERNETES CONCEPTS Deployments Describes a desiredstate of containers and pods Supports: - increasing the number of replicas in a set - rolling out new states - rolling back to older versions - scaling up to facilitate more load - pausing deployments - clean up obsolete sets
- 29. KUBERNETES CONCEPTS Service A Kubernetes Serviceis an abstraction layer which defines a logical set of Pods and enables external traffic exposure, load balancing and service discovery for those Pods. The set of Pods targeted by a Service is usually determined by a selector.
- 30. KUBERNETES CONCEPTS Service Types ClusterIP (default) Exposesthe Service on an internal IP in the cluster. This type makes the Service only reachable from within the cluster. NodePort Exposes the Service on the same port of each selected Node in the cluster using NAT. Makes a Service accessible from outside the cluster using <NodeIP>:<NodePort> LoadBalancer Creates an external load balancer in the current cloud (if supported) and assigns a fixed, external IP to the Service
- 31. KUBERNETES RESOURCE MANIFEST:DEPLOYMENT apiVersion: apps/v1 kind: Deployment metadata: name: hello spec: replicas: 1 selector: matchLabels: app: hello template: metadata: labels: app: hello spec: containers: - name: hello image: runesmith/hello imagePullPolicy: IfNotPresent ports: - containerPort: 8080 name: "http" - containerPort: 5005 name: "debug"
- 32. KUBERNETES RESOURCE MANIFEST:SERVICE apiVersion: v1 kind: Service metadata: name: hello spec: selector: app: hello ports: - name: http protocol: TCP port: 8080 targetPort: 8080 type: LoadBalancer
- 33. KUBERNETES JAVA CLIENT <dependency> <groupId>io.kubernetes</groupId> <artifactId>client-java</artifactId> <version>10.0.0</version> </dependency> ApiClientclient= Config.defaultClient(); Configuration.setDefaultApiClient(client); CoreV1Api api = new CoreV1Api(); V1Pod pod = new V1PodBuilder() .withNewMetadata() .withName("apod") .endMetadata() .withNewSpec() .addNewContainer() .withName("www") .withImage("nginx") .endContainer() .endSpec() .build(); api.createNamespacedPod("default", pod, null, null, null); https://github.com/kubernetes-client/java/
- 34. KUBECTL COMMON COMMANDS kubectlconfig get-contexts # display list of contexts kubectl apply -f ./my-manifest.yaml # create resource(s) kubectl get services, pods, deployments # report on status of services, pods, deployments kubectl logs <pod> # display logs from given pod kubectl rollout history deployment/frontend # Check the history of deployments including the revision kubectl rollout undo deployment/frontend # Rollback to the previous deployment kubectl rollout restart deployment/frontend # Rolling restart of the "frontend" deployment kubectl autoscale deployment foo --min=2 --max=10 https://kubernetes.io/docs/reference/kubectl/cheatsheet/
- 35. WEB UI Dashboard isa web-based Kubernetes user interface. Deploy containerized applications to a Kubernetes cluster, troubleshoot your containerized application, and manage the cluster resources. Get an overview of applications running on your cluster Scale a Deployment, initiate a rolling update, restart a pod or deploy new applications using a deploy wizard. kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0/aio/deploy/recommended.yaml
- 36. LOCAL K8S: MINIKUBE 1.InstallMinikube brew install minikube 2. Start your cluster minikube start 3. Interact with cluster minikube kubectl -- get po –A // download kubectl minikube dashboard // bundled kubernetes dashboard kubectl get po –A // use kubectl to access cluster
- 37. LOCAL K8S: DOCKERDESKTOP 1. Click Docker Desktop icon 2. Click preferences 3. Enable Kubernetes
- 38. KATACODA: INTERACTIVE BROWSER-BASED SCENARIOS Launcha single node cluster Launch a multi-node cluster using Kubeadm Deploy Containers Using Kubectl Deploy Containers Using YAML https://www.katacoda.com/courses/kubernetes/playground
- 39. HELM: THE PACKAGEMANAGER FOR KUBERNETES Packagemanager for Kubernetes Allows you to deploy your app as a single package rather than dealing with multiple manifest files Allows us to manage multiple releases with different configurations Collection of YAML template files, so are text-based and versionable Analagous to apt, yum or homebrew for kubernetes
- 40. DEPLOYMENT PIPELINES: SKAFFOLD SKAFFOLD Skaffoldis a command line tool that facilitates continuous developmentfor Kubernetes-native applications. This enables you to focus on iterating on your application locally while Skaffold continuously deploys to your local or remote Kubernetes cluster.
- 42. ISTIO SERVICE MESH Providesthe fundamentals needed to successfully run a distributed microservices architecture Security Authentication, authorisation and encryption of communication between microservices Observability Provides tracing, monitoring and logging and performance analytics Traffic management Control traffic and API calls between services. Enables A/B testing, traffic shaping and canary testing
- 43. RESOURCES https://github.com/runesmith2013/k8s4j.git Spring boot sampleapp using Docker, Kubernetes, Helm and Skaffold https://www.katacoda.com/courses/kubernetes/playground Browser-based kubernetes playground https://github.com/kubernetes-client/java/ Kubernetes Java client library https://www.docker.com/sites/default/files/d8/2019-09/docker-cheat-sheet.pdf Docker commands cheat sheet https://cloud.google.com/istio Google cloud Istio project https://www.redhat.com/en/topics/microservices/what-is-istio Redhat resources on Istio https://helm.sh/ Helm documentation https://kubernetes.io/docs/reference/kubectl/cheatsheet/ Kubeclt commands cheat sheet https://skaffold.dev/docs/ Skaffold https://www.infoq.com/news/2020/05/java-leyden/ Project Leyden
- 44. RESOURCES https://github.com/kelseyhightower/kubernetes-the-hard-way in depth guideto setting up and running a k8s cluster https://www.linkedin.com/learning/kubernetes-for-java-developers Arun Gupta's course on Kubernetes for Java Developers https://www.magalix.com/blog/create-a-ci/cd-pipeline-with-kubernetes-and-jenkins Go-based tutorial on setting up a pipeline with kubernetes and jenkins