🚦 Traffic Light Docker Challenge

A set of practice tasks for people who new to Docker

Solution (Task-2)

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• The Dockerfile for the apps red, yellow, green are in their respective directories
• The Dockerfile for the nginx-proxy image is in the nginx directory

To create network

• docker network create --subnet=172.20.0.0/16 --gateway=172.20.0.1 traffic-light

Docker run commands

• docker run --rm --network traffic-light --name green-app trafficlight/green:v1.0
• docker run --rm --network traffic-light --name red-app trafficlight/red:v1.0
• docker rrn --rm --network traffic-light --name yellow-app trafficlight/yellow:v1.0
• docker run --rm -p 80:80 -p 3000:3000 -p 4000:4000 -p 5000:5000 --network traffic-light --name nginx-proxy trafficlight/nginx:v1.0
• • NOTE: Mac users may need to disable the Airplay Receiver as it by default runs on port 5000

Solution (Task-3)

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- Run docker-compose up

About The Project

In this project are included a set of tasks designed for beginner Programmers, Systems Administrators, DevOps Engineers, etc. who want to learn or get more familiar with Docker.

Project structure

This project consists of folders appropriately by the color names of a traffic light: red, yellow, and green. Each of them contains the source code of the appropriate web application.

.
├── _config.yml
├── CODEOWNERS
├── LICENSE
├── README.md
├── red
│   ├── app.js
│   ├── Dockerfile
│   ├── favicon.ico
│   ├── package.json
│   └── index.pug
├── yellow
│   ├── app.js
│   ├── Dockerfile
│   ├── favicon.ico
│   ├── package.json
│   └── index.pug
└── green
    ├── app.js
    ├── Dockerfile
    ├── favicon.ico
    ├── package.json
    └── index.pug

1️⃣ Task1: Writing Dockerfiles and building Docker images

1.1 Write a Dockerfile for all applications by following the instructions (from 1.1.1 to 1.1.8) presented below. The created sampler of Dockerfile should be the same for all applications.

• 1.1.1 Docker images must be based on this base image node:17.0-alpine3.14
• 1.1.2 The working directory inside the containers should be the /app directory
• 1.1.3 Copy the package*.json files to the working directory /app before installation of the npm package manager
• 1.1.4 Install the npm package manager via apk (APK stands for Alpine Linux package keeper/manager). The required version of the npm is npm=7.17.0-r0. See how to install packages in Alpine. After the apk instruction install dependency packages with the nmp install command
• 1.1.5 Copy the app.js file to the working directory
• 1.1.6 Copy the index.pug and favicon.ico files to the /app/views/ directory
• 1.1.7 All containers must expose the port 80
• 1.1.8 All containers should execute the following command: node app.js in run time

1.2 Build Docker images for each web app, with following namings:

• trafficlight/red:v1.0
• trafficlight/yellow:v1.0
• trafficlight/green:v1.0

2️⃣ Task2: Running web apps behind Nginx reverse proxy

2.1 Create a docker network with name traffic-light, and assign the 172.20.0.1 as a gateway address with /16 prefix length.

2.2 By using the created images, run containers with following requirements:

• assign the appropriate names: red-app, yellow-app and green-app to containers

• assign the network traffic-light to all containers

2.3 Pull the image nginx:1.21 then run a container with the following requirements:

• assign the name nginx-proxy to the container

• assign the network traffic-light to the container nginx-proxy

• mount the path ~/nginx/conf.d/ of the host to the path /etc/nginx/conf.d/ of the container - for managing configurations from your machine

• the nginx-proxy container must listen to the following ports: 3000, 4000 and 5000. The mentioned ports should map to the web apps as follows: (3000 -> red-app, 4000 -> yellow-app, 5000 -> green-app). 💡 This point must be implemented via nginx_proxy_pass.

If you have done all points of the Task2 correctly, by opening e.g. the link http://127.0.0.1:3000 on your browser, you should see the red-app page. The rest web apps should work with the same logic.

3️⃣ Task3: Running web apps with Nginx load balancing

3.1 Run services via Docker Compose with the following requirements by using the web apps' images that you've built:

• define the following services: red-app, yellow-app, green-app and nginx-load-balancer in docker-compose.yml file
• all the services must share the traffic-light network

3.2 For the nginx-load-balancer service mount the paths from the host to the container as follows:

• ~/nginx/conf.d/ -> /etc/nginx/conf.d/ - by allowing configuration management to be done from the host

• /var/log/nginx/ -> /var/log/nginx/ - by making the Nginx logs accessible on the host

• expose the port 80 for the nginx-load-balancer service

3.3 Make load balancing of request for the all services. 💡 This point must be implemented via Nginx HTTP Load Balancing.

3.4 Restrict access of all web apps with the Nginx HTTP Basic Authentication.

If you have done all points of the Task3 correctly, by visiting with this link: http://127.0.0.1 first time you will see e.g. the red-app, visiting second time (or refreshing the page) you will see e.g. the yellow-app, and for the third time you will see the green-app.