/article_dec_28_mavengradle-based-multi-module-spring-boot-microservices

Containerizing Maven/Gradle based Multi Module Spring Boot microservices using Docker & Kubernetes

Primary LanguageJava

Containerizing Maven/Gradle based Multi Module Spring Boot microservices using Docker & Kubernetes

Maven

  • List all modules under maven project $ mvn help:evaluate -Dexpression=project.modules

  • Build and create docker images for all modules from parent $ mvn clean package spring-boot:build-image

  • Execute maven goal on specific module from parent

$ mvn clean spring-boot:run -pl service-a

$ mvn clean package spring-boot:build-image -pl service-a

Gradle

  • List all projects under gradle project $ gradle -q projects

  • Build and create docker images for all project from parent $ gradle clean build bootBuildImage

  • Execute gradle task on specific project from parent

$ gradle clean :service-a:bootRun

$ gradle clean :service-a:build :service-a:bootBuildImage

Test service via cURL

$ curl http://localhost:8081/greeting

$ curl http://localhost:8082/greeting

$ curl http://localhost:8083/greeting

Docker

  • List Docker images $ docker images | grep spring-multi-module

  • Run a docker image

$ docker run -d -p 8081:8080 -e spring.profiles.active=prod -e serviceb.url=http://<HOST_IP>:8082 -e servicec.url=http://<HOST_IP>:8083 narramadan/spring-multi-module-service-service-a

$ docker run -d -p 8082:8080 -e spring.profiles.active=prod narramadan/spring-multi-module-service-service-b

$ docker run -d -p 8083:8080 -e spring.profiles.active=prod narramadan/spring-multi-module-service-service-c

  • List containers currently running $ docker ps

  • Stop running container $ docker stop <CONTAINER_ID>

  • List all containers that are running or stopped $ docker ps -a

  • Start a container which is not running ````$ docker start <CONTAINER_ID>```

  • Delete docker container $ docker rm <CONTAINER_ID>

  • Delete docker image $ docker rmi <IMAGE_ID>

  • One liner to stop all running containers $ docker stop $(docker ps -a -q)

  • One liner to remove all stopped containers $ docker rm $(docker ps -a -q)

Docker Compose

  • Validate docker-compose file and configuration $ docker-compose config

  • Builds, (re)creates, starts, and attaches to containers for a service. $ docker-compose up -d

  • Lists containers $ docker-compose ps

  • Stops running containers without removing them $ docker-compose stop

  • Starts existing containers for a service $ docker-compose start

  • Stops containers and removes containers, networks, volumes, and images created by up $ docker-compose down

Push to Docker Hub

  • Login to Docker $ docker login

  • Tag docker image before pushing to docker hub if image name is not tagged with docker hub username

$ docker tab <IMAGE_ID> <Docker_Username>/<IMAGE_NAME>

$  docker tag ffc5ec760103 narramadan/springboot-servicea
  • Push to docker hub
$ docker push <Docker_Username>/<IMAGE_NAME>

$ docker push narramadan/spring-multi-module-service-service-a

Deploy to Kubernetes

$ kubectl cluster-info

$ kubectl explain deployment

$ kubectl explain deployment.spec.replicas

$ kubectl explain service

  • Apply deployments & services
  • Order of creation is important. Services should be created before they are to be expanded

$ kubectl apply -f k8s

  • List deployments, services & pods after applying the change $ kubectl get all

  • Watch pods by getting all pods or for a specific app

$ kubectl get pods --watch

$ kubectl get pods -l app=springboot-service-a --watch

  • Scale deployment up/down by setting replicas $ kubectl scale --replicas=2 deployment/springboot-service-a

  • Get Environment Variables set to the pod $ kubectl exec <POD_NAME> -- printenv | grep SERVICE

  • Dump pod logs

$ kubectl logs <POD_NAME>

$ kubectl logs -f <POD_NAME>
  • Delete pods and services $ kubectl delete -f k8s

References