Docker Demo

Docker demo using 5 containers:

• 3 web containers running a REST API
• 1 mongodb server with data persistence
• 1 load_balancer for the web containers

Instructions

Install Docker

Follow the instructions for your OS on this page.

Build the REST API

mvn clean package

Set the Number of Containers

docker-compose scale web=3

Start the Containers

docker-compose up -d

List the running containers

docker-compose ps

Access the REST API

Point your browser to http://127.0.0.1.

Note: if using boot2docker, use the IP contained in the DOCKER_HOST environment variable.

Configuration

Docker

Dockerfile

FROM debian

RUN echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main" | tee /etc/apt/sources.list.d/webupd8team-java.list && \
    echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main" | tee -a /etc/apt/sources.list.d/webupd8team-java.list && \
    apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EEA14886 && \
    apt-get update && \
    echo debconf shared/accepted-oracle-license-v1-1 select true | debconf-set-selections && \
    apt-get install -y oracle-java8-installer oracle-java8-set-default && \
    apt-get clean && \
    rm -rf /var/cache/oracle-jdk8-installer && \
    rm -rf /var/lib/apt/lists/*

RUN groupadd -r docker && useradd -rmg docker docker
VOLUME /tmp
WORKDIR /home/docker
ADD target/*.jar application.jar
RUN touch application.jar
USER docker
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","application.jar"]

Docker Compose

docker-compose.yml

load_balancer:
 image: tutum/haproxy
 links:
   - web
 ports:
   - "80:80"
web:
  build: .
  ports:
   - "8080"
  links:
   - mongodb
mongodb:
  image: mongo

HOWTOs

Connect to a Container

docker exec -it dockerdemo_web_1 bash

View a Container's logs

docker logs dockerdemo_web_1

Add more Containers

Create 2 more instances of the web container

docker-compose scale web=5 && docker-compose up --force-recreate -d

Stop the Containers

docker-compose stop

Update a Container Image

docker-compose build

Remove the Containers

docker-compose rm -f