aws-poc

I had 0 experience with AWS and Terraform before this little project.
The learning was intense, but obviously it was worth it.

This repository contains:

• README.md - What you're currently reading.
• iac/* - A Terraform deployment of 2 EC2 instances, 1 Lambda Function and 1 ALB to balance traffic between them.
• iac/lambda/lambda.(py|zip) - A simple script that returns the time, meant to serve as an AWS Lambda Function.
• iac/populate_ansible_hosts.sh - After running terraform apply, this script can pull the IPs of the instances into the ansible/hosts file.
• ansible/* - A rather simple NGINX deployment for the instances.
• .gitignore - To not have the iac/*terraform* and ansible/hosts files around here.

The logic I chose to implement inside the ALB is this:

• If a request arrives to /time specifically, then it is always forwarded to the Lambda target group.
• Otherwise (and ideally to / because only html/index.html exists in the NGINXs), 50% of the requests are forwarded to the NGINX target group, and 50% are forwarded to the Lambda one.

Prerequisites

• To connect to the instances (and as configured in ansible/ansible.cfg), I used /opt/aws_poc_key.pem as a private key file.
• To authenticate to AWS and allow the public key in the instances, I exported these variables from another file:

  AWS_ACCESS_KEY_ID="<...>"
  AWS_SECRET_ACCESS_KEY="<...>"
  AWS_DEFAULT_REGION="eu-central-1"
  TF_VAR_public_key="ssh-rsa <...>"
  

Steps to deploy

• cd iac/
• terraform init
• terraform plan
• terraform apply
• ./populate_ansible_hosts.sh
• cd ../ansible/
• ansible-playbook setup-nginx.yml
• After the POC, terraform destroy if you want.