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Run Using Docker

We are going to run the Accounts Microservice application available at https://github.com/paulc4/microservices-demo using three docker containers, one for the Eureka registration server and one for each microservice.

Build the Image

  1. Fetch the code using git clone https://github.com/paulc4/microservices-demo

  2. Build using either mvn package or gradle assemble as you prefer.

    This will create the jar: target/microservices-demo-1.2.0.RELEASE.jar

  3. Here is the Dockerfile:

    FROM openjdk:8-jre
ADD target/microservices-demo-1.2.0.RELEASE.jar app.jar
EXPOSE 1111
EXPOSE 2222
EXPOSE 3333

    What this does:

    • Use the OpenJDK 8 docker image (freely available at Docker hub) as a starting point. This image defines a minimal Linux system with OpenJDK 8 preinstalled.
    • Copy the demo jar into the container and rename it to app.jar to save typing later. By default, app.jar will be copied into the root of the container file system.
    • Expose ports 1111, 2222 and 3333.

  4. To build the container (note the . at the end, indicating to use the current directory as its working directory):

    docker build -t paulc4/microservice .

  5. Check it worked. You should see paulc4/microservice listed.

    docker images

Running the Application

We will run the container three times, each time running the Java application in a different mode.

Example Microservices System

  1. They need to talk to each other, so let's give them a network:

    docker network create accounts-net

  2. Now run the first container. This runs up the Eureka registration server, which will allow the other microservices to find each other:

    docker run --name reggo --hostname reggo --network accounts-net -p 1111:1111 paulc4/microservice java -jar app.jar reg

    The -d (detach) flag is missing so all output will stream to the console so we can see what is happening.

    As soon as the application starts up, it displays its IP address. Remember this for later.

  3. In your browser, go to http://localhost:1111 and you should see the Eureka dashboard. There are no instances registered.

  4. In a new CMD/Terminal window, run a second container for the accounts microservice. This holds a database if 21 available accounts (stored using the H2 in-memory RDBMS database)

    docker run --name accounts --hostname accounts --network accounts-net -p 2222:2222 paulc4/microservice java -jar app.jar accounts  --registration.server.hostname=<reg server ip addr>

    Replace <eg server ip addr> with the IP address you determined earlier.

  5. Return to the Eureka Dashboard in your browser and refresh the screen. You should see that ACCOUNTS-SERVICE is now registered.

  6. In a new CMD/Terminal window, run a third container for the accounts web-service. This is a web-application for viewing account information by requesting account data from the accounts microservice.

    docker run --name web --hostname web --network accounts-net -p 3333:3333 paulc4/microservice java -jar app.jar web --registration.server.hostname=<eg server ip addr>

    Replace <eg server ip addr> with the IP address you determined earlier.

  7. Return to the Eureka Dashboard in your browser and refresh the screen. You should see that ACCOUNTS-SERVICE and WEB-SERVICE are now registered.

  8. In a second browser tab, go to http://localhost:3333. This is the web interface you just deployed and you should be able to view, list and search for account information.