DevOps Classroom notes 05/Nov/2025

Scenario – 1: Ntier application infra – AWS

• N tier application
  
• AWS
  
• Concepts:
  • AZ
  • CIDR
• Ips reserved for private usage
  • 10.0.0.0 to 10.255.255.255
  • 172.16.0.0 to 172.31.255.255
  • 192.168.0.0 to 192.168.255.255
• Manual Creation: Watch classroom recording

Working with terraform

• Where are we creating these resources (Provider) => aws
  • account => <your account>
• What are we creating (resources)
• vpc
  • cidr: 192.168.0.0/16
  • Tag:
    • Key: Name
    • Value: from-tf
• subnets
  • web
    • Tag:
      • Key: Name
      • Value: web
    • CIDR: 192.168.0.0/24
    • AZ: ap-south-1a
  • app
    • Tag:
      • Key: Name
      • Value: app
    • CIDR: 192.168.1.0/24
    • AZ: ap-south-1a
  • db
    • Tag:
      • Key: Name
      • Value: db
    • CIDR: 192.168.2.0/24
    • AZ: ap-south-1a
• internet-gateway
• route table:
  • private:
    • Tag:
      • Key: Name
      • Value: private
    • subnet associations:
      • app
      • db
  • public
    • Tag:
      • Key: Name
      • Value: public
    • Route:
      • 0.0.0.0/0 -> igw
    • subnet associations:
      • web
• Order of creation:
  • vpc
    • subnets
    • igw
    • routetables

Configuring aws credentials with terraform

• For this we use aws cli and create a IAM user for terraform (Watch classroom recording)

working with Terrraform

• Create a new folder aws-ntier
• open this folder in vscode
• create a file called as providers.tf in which we configure terraform block and providers

HCL (Haschicorp configuration language)

• Block: generally blocks will be enclosed in { }
  • We have providers block, resources block, datasource block, outputs block, terraform block
  • syntax
    <block-type> {
arg1 = value1
..
argn = valuen
}
• Providers block

provider "<PROVIDER_NAME>" {
  <PROVIDER_ARGUMENTS>
  alias   = "<ALIAS_NAME>"

}

• AWS Provider reference and argument reference
• Provider in Terraform gives
  • Resources
  • Data sources
• In providers.tf write

provider "aws" {
    region = "ap-south-1"

}

• Once the providers is definied execute terraform init