Running Docker Containers on Cloud Foundry

If you are an experienced developer already familiar with Docker, here's a quick way to just deploy your containers into the cloud without having to worry about setting up and managing a Kubernetes cluster. And also important...it comes for free using Cloud Foundry.

Let's start by creating a simple NodeJS application locally using 'npm init', give your app a name e.g. 'tinyapp' and use 'server.js' as the entry point. 

This will generate a 'package.json' file:

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    {

      "name": "tinyapp",

      "version": "1.0.0",

      "description": "",

      "main": "server.js",

      "scripts": {

        "test": "echo \"Error: no test specified\" && exit 1"

      },

      "author": "",

      "license": "ISC"

    }

Next install the NodeJS 'Express-framework' using the command: 

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# npm install express --save 

Create a NodeJS application file 'server.js'

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const express = require('express');

const app = express();

const port = process.env.PORT || 3000;

 app.get('/', (req,res) => res.send('Hello there !!!'));

 app.listen(port, () => console.log(`Example app listening on port ${port}!`));

Test the NodeJS application locally using the command:

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 # node server.js

This will launch the app locally to listen on port 3000. You can verify the working of the app with a  browser http://localhost:3000.

Now we can already deploy this app onto Cloud Foundry with the standard NodeJS runtime buildpack using the command: 

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# cf push tinynodejs 

Once the deployment is done we can test the app using the given URL with Curl or with a Web Browser.

Of course you will need an IBM CLoud account for this. 

If you don't have an account yet, you can register for a free Lite account here: https://ibm.biz/freeaccount.

More details on using the IBM Cloud CLI can be found here: https://cloud.ibm.com/docs?tab=develop

You might get an error during deployment as Cloud Foundry will try to deploy your app using 1Gb of memory by default and with a lite account you're limited to 256M. In order to resolve this you can create a manifest.yaml file from your failed deployed application using the command :

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# cf create-app-manifest tinynodejs -p manifest.yaml 

Edit the local manifest.yaml file and change the memory to e.g. 128M and do a 'cf push' again.

This is the most common way to deploy an applcation using a Cloud Foundry runtime.

Let's now 'Dockerize' our application:

First we need to create a 'Dockerfile' with following content:

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FROM node

WORKDIR /app

COPY package.json /app

RUN npm install

COPY . /app

CMD node server.js

EXPOSE 8080

Perform a Docker build:

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# docker build . -t tinyapp

Verify the Docker image was stored successfully:

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# docker images

REPOSITORY     TAG           IMAGE ID            CREATED             SIZE

tinyapp        latest        e30aeb035b14        59 seconds ago      948MB

Run the container locally:

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# docker run -p 8080:3000 -d tinyapp

Verify the container is running:

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# docker ps

CONTAINER ID IMAGE   COMMAND                CREATED       STATUS        PORTS       

1e8571529040 tinyapp "docker-entrypoint.s…" 7 minutes ago Up 7 minutes  8080/tcp, 0.0.0.0:8080->3000/tcp   hungry_montalcini

Verify access to the application using http://localhost:8080 as the initial port 3000 is now mapped to port 8080 on Docker.

You can also execute a shell command into the container using the 'CONTAINER ID': 

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# docker exec -it 1e8571529040 /bin/bash

Next we can deploy this docker image to the cloud using Cloud Foundry 'cf push' command but before we do that we will first clean up the existing app:

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    # cf delete tinynodejs

Caution here because deleting the app does not delete the application route ! 

You can check the Cloud Foundry routes with:

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    # cf routes

So let's also delete the existing route: 

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# cf delete-route eu-de.mybluemix.net --hostname tinynodejs

And now let's deploy the Docker container:

First we need to upload our Docker image to a central container repository e.g. https://hub.docker.com

• Login to Dockerhub:

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# docker login --username=<your username>

• Tag local image using the 'IMAGE ID'

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# docker tag e30aeb035b14 ydebeer/tinynodejs:latest

• Push the image to your Dockerhub repository:

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# docker push ydebeer/tinynodejs:latest

Now we can push the image to run on the IBM Cloud using CLoud Foundry:

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# cf push tinynodejs -o ydebeer/tinynodejs:latest

And there you have it: a NodeJS app running as a Docker container in the IBM Cloud.