Deploying Spring Based WAR Application to Docker

Docker Tutorial - Table Of Contents
Docker 
Deploying Spring Based WAR Application to Docker
Deploying Spring Based JAR Application to Docker
Deploying Multiple Spring Boot Microservices using Docker Networking
Deploying Multiple Spring Boot Microservices using Docker Compose
Deploying Spring Boot + MYSQL Application to Docker
Publishing Docker Image to DockerHub
 Deploy Docker Swarm services using Play With Docker
 Deploy Docker Swarm services using Docker Stack
 Deploy Docker Swarm services to multiple AWS EC2 instances
Docker Cheat Sheet

In a previous tutorial we had created a simple Spring Boot Web Application named employee-producer, that exposed a REST web service. This was developed to be deployed using WAR packaging.
We will be creating an image for deploying this war application to tomcat.

Create the dockerfile. Docker file is a list of commands that we want the docker engine to execute. We will be needing a tomcat image using which we will be deploying our application. Go to dockerhub and search tomcat, we will be using official tomcat images. Here since we are using jdk 8 so we select alpine 8.


Go to the spring boot project folder and create a docker file as follows-

From tomcat:8.0.51-jre8-alpine
CMD ["catalina.sh","run"]

Open the terminal and install the docker

yum install docker

Another terminal, start the docker

systemctl start docker

Now open the terminal and go to the Spring Boot project folder.
Next we will build an image with the name producer.

docker image build -t employee-producer .

Next we will run the above image as a container

docker container run -d employee-producer

Here we have started the container. Now using the following command check the logs

docker container logs lb

The application has started successfully. If we go to localhost:8080 we see that tomcat is not running.

This is because tomcat would have started inside the docker on port 8080. But we cannot access this port directly since its running inside the docker.


Now stop the existing running container-

Again run the image as a container but this time using the publish command where we link the docker internal port 8080 to external port 8080, so that it can be accessed externally.

docker container run -p 8080:8080 -d employee-producer

Now go to localhost:8080



So we have linked the docker internal port 8080 to our external port 8080. Now go to localhost:8080 and we can see that tomcat has started successfully.
Next we will see how to go inside the docker and investigate it using the docker exec command.

docker container exec -it 03 /bin/sh

We will need to copy our WAR file in the webapps folder of the tomcat inside the docker. This we will do it adding commands to the docker file.

From tomcat:8.0.51-jre8-alpine
RUN rm -rf /usr/local/tomcat/webapps/*
COPY ./target/employee-producer-0.0.1-SNAPSHOT.war /usr/local/tomcat/webapps/ROOT.war
CMD ["catalina.sh","run"]

Now stop the docker container we had previously started.

docker container stop 03

Again build the image, and start the container.



Go to localhost:8080/employee, we will see that our application is deployed successfully.