Deploying Java Applications on Oracle Cloud

This repository how to use Docker and Kubernetes with Java Applications.

Requirements

• Docker: https://www.docker.com/products/docker-desktop
• Maven: https://maven.apache.org
• Kubectl: https://kubernetes.io/docs/tasks/tools/install-kubectl/
• Oracle Kubernetes Engine OKE: https://cloud.oracle.com/home

The Java Application

The javaee-cafe is the basic Java EE 8 application used throughout the Docker and Kubertenes demos. It is a simple CRUD application. It uses Maven and Java EE 8 (JAX-RS, EJB, CDI, JPA, JSF, Bean Validation).

You can use any Maven capable IDE such as NetBeans. We use Open Liberty but you should be able to use any Java EE 8 compatible application server such as WildFly or Payara. We use Postgres but you can use any relational database such as MySQL.

The application is composed of:

• A RESTFul service:* protocol://hostname:port/javaee-cafe/rest/coffees

  • GET by Id: protocol://hostname:port/javaee-cafe/rest/coffees/{id}
  • GET all: protocol://hostname:port/javaee-cafe/rest/coffees
  • POST to add a new element at: protocol://hostname:port/javaee-cafe/rest/coffees
  • DELETE to delete an element at: protocol://hostname:port/javaee-cafe/rest/coffees/{id}

• A JSF Client: protocol://hostname:port/javaee-cafe/index.xhtml

Docker

• Open a console. Add maven to PATH:

   export PATH=/Library/Maven/apache-maven-3.5.0/bin/:$PATH
  

• Navigate to where you have this repository code in your file system. Compile and Package the application via maven:

   mvn package -f javaee-cafe/pom.xml 
  

• Copy the .war file into docker directory:

   cp javaee-cafe/target/javaee-cafe.war docker/
  

• Make sure Docker is running. Build a Docker image tagged javaee-cafe issuing the command:

   docker build -t javaee-cafe docker/.
  

  Note: If your Docker instance is running on Linux/Windows before to build the Docker image it is necessary to open the file server/server.xml and edit the serverName="docker.for.mac.localhost" of the dataSource to serverName="localhost"

Deploying the application with Docker

• Make sure Docker is running. Open a console.

• Enter the following command and wait for the database to come up fully.

   docker run -it --rm --name javaee-cafe-db -v pgdata:/var/lib/postgresql/data -p 5432:5432 postgres
  

• To run the newly built image, use the command:

   docker run -it --rm -p 9080:9080 javaee-cafe
  

• Wait for Open Liberty to start and the application to deploy sucessfully (to stop the application and Liberty, simply press Control-C).

• Once the application starts, you can test the REST service at the URL: http://localhost:9080/javaee-cafe/rest/coffees or via the JSF client at http://localhost:9080/javaee-cafe/index.xhtml.

Kubernetes

Pushing the Docker image to Docker hub

• Copy the .war file into kubernetes directory:

   cp javaee-cafe/target/javaee-cafe.war kubernetes/
  

• Log in to Docker Hub using the docker login command:

  docker login
  

• Build a Docker image and push the image to Docker Hub:

  docker build -t <your Docker Hub account>/javaee-cafe:<your docker image version> kubernetes/.
  docker push <your Docker Hub account>/javaee-cafe:<your docker image version>
  

Deploying the Application on Oracle Kubernetes Engine

• Open a terminal.

• List the containers running in a Cluster:

  kubectl get pods
  

• Start the proxy to the Kubernetes API server:

  kubectl proxy
  

• Once the Oracle Kubernetes Engine Console starts, you can login at the URL: http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/login

• Deploy postgres with a persistent volume claim with the following command:

  kubectl create -f kubernetes/postgres.yml
  

• Get the pod for Postgres:

  kubectl get pods
  

• Connect to Postgres:

  kubectl exec -it postgres-<VER POD> -- psql -U postgres
  

• On Postgres and run the command \dt to see the tables, '\q' to logout Postgres

• Create a config map with the hostname of Postgres:

  kubectl create configmap hostname-config --from-literal=postgres_host=$(kubectl get svc postgres -o jsonpath="{.spec.clusterIP}")
  

• Replace the <your Docker Hub account> value with your account name in kubernetes/javaee-cafe.yml file, then deploy the application:

  kubectl create -f kubernetes/javaee-cafe.yml
  

• Get the External IP address of the Service, then the application will be accessible at http://<External IP Address>:9080/javaee-cafe:

  kubectl get svc javaee-cafe
  

  Note: It may take a few minutes for the load balancer to be created.

• Scale your application:

  kubectl scale deployment javaee-cafe --replicas=3
  

Deleting the Resources

• Delete the Java EE deployment:

  kubectl delete -f kubernetes/javaee-cafe.yml
  

• Delete the hostname config map:

  kubectl delete cm hostname-config
  

• Delete Postgres:

  kubectl delete -f kubernetes/postgres.yml