Aspen Take Home Project

This project is for implementing the Aspen Capital DevoOps/SRE take-home project defined here.

Project Overview

This project uses AWS' Cloud Development Kit (CDK) implemented in Python to provision a single EC2 instance with the following architecture:

This project consists of three main components - the provided express application, the NGINX load balancer, and CDK for deploying and provisioning the project.

Implementation Explanation

Due to the requirements of a single NGINX reverse proxy forwarding to two instances of the application, EC2 seems like the best choice for this implementation. If we needed multiple instances with each having its own reverse proxy, an ECS with a sidecar implementation would have been a better choice. ECS excels in providing its own load balancing with multiple instances of the same container (app in this case), so NGINX would have been redundant and the sidecar implementation would not have fit the requirements.

Other alternatives considered were using fargate as well as other serverless containerization services. Ultimately, EC2 felt the most appropriate given the requirements and budget constraints as part of this exercise was to utilize the free tier as much as possible to show the ability to analyze and stay within a budget.

Languages and Tools:

The provided app was written in express node.js while the CDK deployment was implemented in python. I chose to use docker containers for each of the apps and the NGINX instance in order to simplify orchestration using docker-compose. Shell scripts were also used extensively to help with provisioning the deployed system, as well as starting the express app (and keeping the container running), building and deploying the docker images.

Pre-Requisites:

1. Make sure you have aws-cli installed and configured before using CDK to deploy the project. If you want to use a seperate account and region you may set the variables in .env in the cdk project subfolder.

2. Make sure you have python3 and venv installed for use with the cdk.

3. If you want to run the project locally, make sure you have docker and docker-compose installed.

Getting Started Deploying to AWS:

The general workflow for building and deploying the application to AWS:

1. Clone the project into the desired location:

git clone https://github.com/JaimeLanders/Aspen-Take-Home-Project.git

2. Create .env in the cdk subfolder (.env_example provided for ease) to customize the deployment.

cp ./cdk/.env-example ./cdk/.env 

3. Bootstrap and deploy the application to the desired account and region in the cdk subfolder:

cd ./cdk

cdk synth

cdk boostrap

cdk deploy

4. Tear down the instance

cdk destroy

Getting Started Deploying Locally:

The general workflow for building and deploying the application locally:

Note: The startlocal.sh script has been provided to run steps 1/2.

1. To deploy the project locally, first create the docker network:

sudo docker network create -d bridge aspen

2. Then use docker-compose to build and deploy the project in the project root:

sudo docker-compose scale app=2 nginx=1

3. Next, curl or visit https://localhost or http://localhost in your browser:

curl -k https://localhost

curl http://localhost

4. You should see something similar to the following in your browser and/or terminal:

{"hostname":"a7c40351918a","msg":"Hello world!","nodeVersion":"v18.2.0","pid":43,"uptime":7867.478466045}

{"hostname":"4abc1126b96c","msg":"Hello world!","nodeVersion":"v18.2.0","pid":42,"uptime":7876.017861105}

Note that the hostname is the app container and they will alternate between both containers due to the NGINX load balancer.

5. To tear down the application, you can run the stop.sh helper script or run the following commands:

sudo docker-compose down

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Visit the cdk, app and nginx project subfolders for more details and instructions.