Deploy Java Spring server with Docker container

I am deploying a Java Spring server using Docker. Here are the steps:

1. Launch a ubuntu server

In this demo, assume you have a server launched with ubuntu 14.04. Install docker via APT repository:

$ sudo apt-get update

$ sudo apt-get install apt-transport-https ca-certificates

$ sudo apt-key adv — keyserver hkp://p80.pool.sks-keyservers.net:80 — recv-keys 58118E89F3A912897C070ADBF76221572C52609D

Open /etc/apt/sources.list.d/docker.list with your favorite editor and add this line:

deb https://apt.dockerproject.org/repo ubuntu-trusty main

Install docker in the server as follow:

$ sudo apt-get update

$ sudo apt-get install docker-engine

$ sudo service docker start

2. Build Docker image

$ docker login

with your username and password.

In your local development Java spring folder, create a Dockerfile like this:

FROM frolvlad/alpine-oraclejdk8:slim
VOLUME /tmp
ADD target/fleet-beacon*.jar app.jar
EXPOSE 8080
RUN sh -c ‘touch /app.jar’
ENTRYPOINT [“java”, “-jar”,”/app.jar”]

And build the image:

$ docker build -t username/repo-name .

*where -t stands for tag,
*replace username and repo-name with your namespace.
*also don’t forget the dot .

Push the image to your remote repository:

$ docker push username/repo-name

3. Pull the docker image

In your remote ubuntu server, docker login and pull the image:

$ docker pull username/repo-name

Run it in the background

$ docker run -d -p 8080:8080 username/repo-name

*where -d means detached,
*-p means publish all exposed ports to the host interfaces, for example 8080 to 8080.

4. Nginx setup

With the vim editor, open the file in /etc/nginx/sites-available/default, and edit as follow

server {
 listen 80 default_server;
 listen [::]:80 default_server ipv6only=on;

 root /usr/share/nginx/html;
 index index.html index.htm;
 server_name localhost;

location / {
  proxy_set_header X-Forwarded-Host $host;
  proxy_set_header X-Forwarded-Server $host;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_pass http://localhost:8080/;
}

Exit and save with :wq! that’s it. Open a browser and point to your remote server IP, you should be able to see the Java Spring page running.

5. Troubleshooting

Sometimes if you encounter a problem with the daemon connection:

Cannot connect to the Docker daemon. Is the docker daemon running on this host?

Run the command:

$ eval $(docker-machine env default)

If your are testing locally and couldn’t find your IP address, try this command to find the IP:

$ docker-machine ls

Leave a comment below if you encounter other issues as well.

Victor Leung