Infrastructure as Code (IAC)

• The basic idea behind IAC is to write and execute the code to define, deploy, update and destroy your infrastructure
• We need to treat all aspects of operations as software (Event those aspects of setting up servers)
• Five Broad categories of IAC
  • Adhoc Scripts:
    • Examples: Shell Script, Powershell Script
  • Configuration Management tools:
    • Examples: Chef, Ansible, Puppet, Salt Stack
  • Server Templating Tools:
    • Examples: Packer, Vagrant, Docker
  • Orchestration Tools:
    • Examples: Kubernetes, Apache mesos etc
  • Provisioning tools:
    • Examples: Cloud formation, ARM Templates, Terraform

Terraform

• This is a tool for building, changing and versioning infrastructure safely and effeciently
• To express our Infrastructure as a code Terraform has its own Domain Specific Language (DSL)
• To understand how terraform works, we need to know two key terms
  • Resource: This is piece of infrastructure which you want to create.
  • Provider: This tells terraform where the infrastructure has to be built/created.
• Basic Terraform Workflow
  • In Terraform, we configure Providers which specify where the infra has to be created
  • We also configure resources, which specify what has to be created
• Terraform is tool which is written in a GO Language, which interacts with Provider api
• Terraform Language Refer Here
• Terraform supports many providers Refer Here
• Each Provider provides resources which we can use to write in a template

Hello-Terraform

• Lets create a very simple terraform template to create s3 bucket in AWS
• To do this we need to know
  • How to create the infrastructure manually
  • How to configure the provider to create resource (s3 bucket) in terraform configuration language
  • In this case since we need to create in aws lets view the aws provider Refer Here and for documentation Refer Here
• Lets see the steps to create s3 bucket
  • Login into aws console
  • Navigate to s3
  • Click on Create bucket
• Lets see how to create this from terraform
  • create a new folder and create a file called as main.tf
  • .tf is extension for terraform
• In Terraform Arguments are the inputs which you provide and Attributes are the outputs which terraform provides upon execution.
• Now lets try to setup provider and also provide authentication information Refer Here
• Creating Access Key and secret key in AWS
  • official docs Refer Here
  • for image demonstration Refer Here
• Lets write a terraform template to configure the resource and provider
• Now lets execute the terraform by executing following commands

terraform init
terraform validate --help
terraform validate .
terraform apply --help
terraform apply .
terraform destory .

• By default terraform is a single executable that is downloaded into your machine, if you want to execute terraform we need providers. When we execute terraform init your respective provider gets downloaded
• Template developed in class

provider "aws" {
   region   = "ap-south-1"
   access_key = "your access key"
   secret_key = "your secret key"
}

resource "aws_s3_bucket" "mybucket" {
    bucket = "qts3fromtffeb21"
}