Terraform and Ansible - DevOps Challenge

This project uses Terraform to automate the creation and configuration of a reliable infraesctructure in Amazon Web Services. It also uses Ansible to configures the servers (EC2 instances) to host and run a nodejs Chat application.

Project Requirements:

• An AWS account or IAM user with the necessary permissions to create the infraestructure mentioned in the Terraform Tasks Section.
• AWS CLI tools configured with your AWS account or IAM user.
• Terraform CLI tools installed (v0.15.3).
• Ansible CLI tools installed (v2.9.21).

Note: follow the links above to find install instructions of every required tool.

Terraform Tasks:

• Create a VPC with 2 public subnets in different availabilty zones.
• Create an Internet Gateway and a Route Table for the VPC created.
• Create an Elastic Load Balancer for 2 Amazon EC2 running the chat app.
• Create a security group for the ELB for HTTP access.
• Creates 2 Amazon EC2 [t2.micro] instances based in an Ubuntu AMI. One in each public subnet.
• Create a security group for the EC2 instances for HTTP and SSH access.
• Create a SSH key to access the EC2 instances.
• Upload a shell script to install nodejs and npm in the EC2 instances.

Ansible Tasks:

• Run the script to install nodejs and npm.
• Create a directory to download the chat app git repo.
• Download the Chat App Repo from Github.
• Install node packages dependencies for the Chat App Repo.
• Install PM2 package to manage node servers (EC2 instances).
• Start nodejs in node servers to host the Chat App.
• Configure PM2 to start node servers on every server startup.

Project Technical Details

Terraform Variables

Variable	Description
aws_region	Name of the region where AWS infraestructure will be created.
aws_availability_zone_a	Name of the availabilty zone 'A'.
aws_availability_zone_b	Name of the availabilty zone 'B'.
application	Name of the node application to run.
ami	AMI id used to create the EC2 instances.
public-ssh-key-path-file	Local path to the public ssh key (.pub) file generated. This is passed with -var option when 'terraform apply', 'terraform plan' or 'terraform destroy' commands are executed.
private-ssh-key-path-file	Local path to the private ssh key file generated. This is passed with -var option when 'terraform apply', 'terraform plan' or 'terraform destroy' commands are executed.

Project Execution:

Note: this instructions were tested in Ubuntu 18.04 but could work without major changes in some other linux distributions.

Clone this repository in your preferred folder

git clone https://github.com/ErickHernandez/Chat-App-using-Socket.io.git ChatApp
cd ChatApp

Generate a SSH key without passphrase

mkdir sshkeys && cd sshkeys
ssh-keygen -f nodekey

Note: the console will ask you for a passphrase, just press enter twice.

Build the required infraestructure with Terraform

cd ../terraform
terraform init
terraform apply -var "public-ssh-key-file=../sshkeys/nodekey.pub" -var="private-ssh-key-file=../sshkeys/nodekey"
type 'yes' (without single quoutes) and press enter

Note: This process may take 10-15 minutes to create all the infraestructure requiered. When the process finish it will output the ec2 instances public ip's and the ELB dns to access the chat app (after finishing all the steps).

Add the public ip's in Ansible host file

Copy the public ip's that the previous command printed as output and add them to the Ansible hosts file.

sudo nano /etc/ansible/hosts

Note: Paste the public ip's one per line below the [webservers] tag, in case it doesn't exist then create it.

Configure your SSH private key in Ansible

Set the generated ssh private key file path to the enviroment variable ANSIBLE_PRIVATE_KEY_FILE

export ANSIBLE_PRIVATE_KEY_FILE=<absolute-path-to-the-repo-cloned>/sshkeys/nodekey

Run the Ansible Playbook

This will install nodejs, download the repo with the Chat App and install it's dependencies in the EC2 instances. It also will start the node server.

cd ../ansible
ansible-playbook ansible.yaml -u ubuntu

Note: If the EC2 instances are not created yet you could get an error like this: fatal: [3.238.139.180]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Host key verification failed.", "unreachable": true}

In case of that check that the ec2 instances are up and running and then re-run the ansible command again.

Test the Chat App website

1. Copy the ELB dns name that the terraform apply command printed in the output.
2. Open you web browser and paste the ELB dns name.

Clean Up AWS Infraestructure Instructions

The following instructions will destroy all the infraescture created by terraform.

cd ../terraform
terraform destroy -var "public-ssh-key-file=../sshkeys/nodekey.pub" -var="private-ssh-key-file=../sshkeys/nodekey" 
type 'yes' (without single quoutes) and press enter