Terraform

Activity 5: Create an RDS in AWS

• To create rds instance we need
  • vpc
  • subnet group (group of 2 or more subnets)
  • security group
  • database details
    • engine (mysql, oracle, …)
    • size (db.t2.micro or db.t3.micro)
    • credentials
• For this activity lets try using
  • default vpc
  • default subnet group
  • create a security group

Terraform Backends

• Backend represents the location in which the terraform state file is stored
• Default backend is local folder
• Terraform support different backend types
  • local
  • remote
  • s3
  • azurerm
  • gcs
  • ..
• Backend also needs locking
  • S3 backend doesnot support locking, so we need to provide dynamo db as extra configuration for lockig
  • azurerm supports locking
• Watch classroom video for further illustration.

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = ">= 5.82.2"
    }
  }
  required_version = ">= 1.10.0"
  backend "s3" {
    bucket = "ltterraformstates"
    region = "us-east-1"
    key = "backendtest/terraform.tfstate"
    dynamodb_table = "ltterraformlock"
  }
}

Terraform Modules

• Terraform modules are reusable terraform templates
• For resource or backend
  • input => argument
  • output => attribute
• For module
  • variables acts as arguments
  • outputs act as attributes
• Community Modules are available in terraform registry for public usage
• To use a module we create a module block

module "security-group" {
  source  = "terraform-aws-modules/security-group/aws"
  version = "5.3.0"
}

module "web_server_sg" {
  source = "terraform-aws-modules/security-group/aws//modules/http-80"

  name        = "web-server"
  description = "Security group for web-server with HTTP ports open within VPC"
  vpc_id      = "vpc-12345678"

  ingress_cidr_blocks = ["10.10.0.0/16"]
}

• When we create Modules, modules will not have provider block, templates do

Lets create our own AWS VPC Module

• Refer Here for the changes

Lets use community module to create a security group

• Security opening 80 and 443 ports for all
• module link
• Refer Here for the changes done