instance-details

instance-details lets you easily create infrastructure on AWS and deploy an application that displays the information of all running EC2 instances.

Project breakdown

• Creating an application to return a list of all running EC2 instances in a region in an AWS account along with their corresponding IPs and Tags when called on the /ec2 path
• Building and pushing container image of the application to the registry
• IaC(Infrastructure as Code) to automate the deployment of infrastructure on AWS

Tech stack:

	Technology		Description
✦	Python		programming language
		pip	package-management system
		flask	micro web framework
		gunicorn	web server gateway interface HTTP server
		boto3	python SDK for AWS
✦	Docker		containerization platform
✦	AWS		public cloud platform
		instance	virtual server
		launch template	launch parameters for instance
		ASG	Auto Scaling group: logical grouping of instances
		target group	request routing to registered targets
		ALB	Application Load Balancer: configuring and routing incoming end-user traffic to apps
		route 53	Domain Name System service
		security Group	virtual firewall
✦	Terraform		infrastructure as code software tool

Initial steps

• Install AWS CLI
• Create AWS credentials
• Configure the above AWS credentials locally by inserting respective values

  aws configure
  

Application creation and containerization steps can be found here.

Infrastructure deployment

Resources are segregated as per the services and their components. More details in respective directories.

Dependencies

• Terraform

Features

• Modularized structure
• Terraform backend state maintained in S3 bucket with versioning enabled
• Isolation between the terraform tfstate files for the AWS resources for reducing the impact
• Terraform tfvars used for passing variable values
• Consistent structure and naming convention

Backend configuration

• Best for teams to store the Terraform state file remotely
• Teams have access to the latest copy of infrastructure always
• Supports state locking and consistency checking
• Three things are required:
  • Terraform S3 backend resource
  • S3 bucket to store the state file
  • DynamoDB table for state locking and consistency checking

  terraform {
    backend "s3" {
      bucket         = "example-s3"
      key            = "path/to/my/key" // e.g "prod/route_53.tfstate"
      region         = "us-east-1"
      encrypt        = "true"
      dynamodb_table = "example-table"
    }
  }

Terraform resources structure

├── README.md                 // Description of the module and its purpose
├── backend.tf                // To create terraform backend state configuration
├── data.tf                   // It contains the declarations for data sources
├── main.tf                   // The primary entrypoint for terraform resources
├── outputs.tf                // It contains the declarations for outputs
├── terraform.tfvars          // The file to pass the terraform variables values
├── variables.tf              // It contains the declarations for variables
├── versions.tf               // To specify terraform versions and providers

Resource provisioning order

1. DynamoDB Table
2. S3
3. VPC
4. EC2
5. Route 53

Provisioning steps

1. Head over to the path of the resource to be deployed

2. Run

   terraform init
   

   terraform plan
   

   terraform apply
   

   Command	Description
   terraform init	initializes a working directory containing Terraform configuration files
   terraform plan	creates an execution plan, which lets us preview the changes that Terraform plans to make to our infrastructure
   terraform apply	executes the actions proposed in the Terraform plan

   Note: Above commands should be run from the resource directories. The modules directory consists of root modules and will not change anything unless it is necessary.

Terraform directory structure

├── dynamodb_table
│   ├── main.tf
│   ├── outputs.tf
│   ├── README.md
│   ├── terraform.tfvars
│   ├── variables.tf
│   └── versions.tf
├── ec2
│   ├── backend.tf
│   ├── main.tf
│   ├── outputs.tf
│   ├── README.md
│   ├── terraform.tfvars
│   ├── variables.tf
│   └── versions.tf
├── modules
│   ├── dynamodb_table
│   │   ├── main.tf
│   │   ├── outputs.tf
│   │   ├── variables.tf
│   │   └── versions.tf
│   ├── ec2
│   │   ├── data.tf
│   │   ├── main.tf
│   │   ├── outputs.tf
│   │   ├── user_data.sh
│   │   ├── variables.tf
│   │   └── versions.tf
│   ├── route_53
│   │   ├── data.tf
│   │   ├── main.tf
│   │   ├── outputs.tf
│   │   ├── variables.tf
│   │   └── versions.tf
│   ├── s3
│   │   ├── main.tf
│   │   ├── outputs.tf
│   │   ├── variables.tf
│   │   └── versions.tf
│   └── vpc
│       ├── data.tf
│       ├── main.tf
│       ├── outputs.tf
│       ├── variables.tf
│       └── versions.tf
├── README.md
├── route_53
│   ├── backend.tf
│   ├── main.tf
│   ├── outputs.tf
│   ├── README.md
│   ├── terraform.tfvars
│   ├── variables.tf
│   └── versions.tf
├── s3
│   ├── main.tf
│   ├── outputs.tf
│   ├── README.md
│   ├── terraform.tfvars
│   ├── variables.tf
│   └── versions.tf
└── vpc
    ├── backend.tf
    ├── main.tf
    ├── outputs.tf
    ├── README.md
    ├── terraform.tfvars
    ├── variables.tf
    └── versions.tf