Lab 002 - Create a basic container using Dockerfile¶

In this lab we will create our first container using Dockerfile
The container will be used to serve a simple NodeJs web server
No NodeJs knowledge is required
You will need to create, build, tag & push your container to DockerHub
The lab is divided into the several tasks.

01. Prepare the server code¶

Our container will include the following NodeJs simple web server

Copy the code below and save it to a file named server.js

//
// Filename: server.js
//
// Simple NodeJs Server
// The server is listening by default to port 8888
//

// import the HTTP module
var http = require('http');

// Define a port we want to listen to
// Later on we will pass the port as env parameter
// Default port is set to 8888
const PORT= process.env.PORT || 8888; 

// Create the server and listen for requests
// Create the server and listen for requests
http.createServer((request, response)=>{
    response.end('Server is running.!! You asked for: ' + request.url);
}).listen(PORT, ()=>{
    // Callback is triggered when server is getting a request
    console.log("Server listening on: http://localhost:%s", PORT);
});

02. Test the `server.js` code¶

Before we “pack” our code in Docker image lets test the code

We will test the code inside nodejs docker

# Test the node code
#   --rm            =   remove the container when done
#   -d              =   run in detached mode
#   -p              =   open the required ports
#   -v              =   volume
#   -w              =   workdir
#   --name          =   the container name
#   node            =   Execute a nodejs container to test our code
#   node server.js  =   Execute the code
docker   run --rm -d       \
  -v     $(pwd):/usr/src  \
  -w     /usr/src         \
  -p     8888:8888        \
  --name node_server      \
  node                    \
  node server.js

03. Write the `Dockerfile`¶

Now lets create a Dockerfile with the code we just created above

The Dockerfile will be based upon nodejs image and will include our server.js

#
# Filename: Dockerfile
#
# Use node as our base image
FROM      node

# Optional: Set working directory
WORKDIR   /usr/src

# Copy the server code to our working directory [.]
COPY      server.js .

# Mark the port which will required for the server
EXPOSE    8888

# Start the server when the container is started
CMD       ["node", "./server.js"]

04 - Build the image¶

Once we have the docker file we can build the image
Once the image is ready we will push it to DockerHub so you will need an account.

We will name the image: “Your Dockerhub username/repository:version”

###
### Build the image
### Tag the image with the following 
###     DockerHub username/repository:version
###
docker build -t nirgeier/docker-labs-002 .

Login to DockerHub
Execute docker login and enter your Docker Hub credentials when prompted
If you don’t have a DockerHub account, create one at https://hub.docker.com/signup
You will need to push the image to DockerHub in the next step

06. - Push the image to DockerHub¶

Docker Login Required

You must login to Docker Hub before you can push to DockerHub

Example: docker push username/image:tag

07. Verify the push¶

Login to your DockerHub account and verify that the image exists under your DockerHub account.

08 - Test the image¶

Last step is to test our image
To do so we will pull and run the image from DockerHub

Once the container is started we will test the server

###
### Pull the image from DockerHub
###  Replace the image tag with your image tag
### 
docker   run -d               \
        --name 002-container \
        -p 8888:8888         \
        nirgeier/docker-labs-002

### Check that the container is working as expected
docker logs 002-container

09. Test the server¶

Test the server that he is running on docker.

# Test the server that he is running on docker
curl -s localhost:8888

### ExpectedOutput:
Server is running.!! You asked for: /

10. Clean up¶

Stop and remove the container

# Stop the container
# If we used --rm the container should remove itself
docker stop 002-container

# If not used --rm - remove the container
docker rm 002-container

Well Done