1. Create instance with terraform features

2. Create instance from UI and use the key next time

3. Create instance use the public key inside the file

4. Create an instances using: resource "aws_key_pair" "my_key" { key_name = "my_key" public_key = "" }

5. Create an instance using the key_name = "${file("public_key"}"

6. Create an instance with userdata

    user_data = "${file("user_data")}"
   

7. Create an instance with vars inside the file like this

variable "ami" { default = "ami-oololol" } and use it inside the instance block

resource "aws_instance" "my-instance" { ami = "${var.ami}"

9. Create a vars.tf file with the ami names from AWS variable "awsami" { default = "ami-slsldfldfld" }

variable "centos7" { default = "centos-ami-dlldldl" }

use it inside the file resource "aws_instance" "my-instance" { ami = "${var.ami}"

Create a variable with variable "micro" { default = "t2.micro" }

variable "awsami" { default = "ami-0b59bfac6be064b78" } variable "micro" { default = "t2.micro" } variable "dev" { default = "Dev_Environment" }

use it inside the file

11. Use count option to create multiple instances on aws resource "aws_instance" "my-instance" { ami = "${var.ami}" instance_type = "t2.micro" key_name = "{var.my_key}" user_data = "${file("user_data")}" count = 4 }

12. Use terraform provider file instead of same place. vim provider.tf

provider "aws" { region = "us-east-2" }

13. Create count.tf file and add the following to that variable "instance_count" { default = 1 #10 } Inside the terraform.tf file add the following count = "${var.instance_count}"

This will create the default number of instance for us. Pay attention to tag

tags { ENVIRONMENT = "Dev-${count.index}" } This will create Dev-1 tag on the instances.

Terraform import

The reason: If the environment is created by terraform, but some user also creates an instance on the same region. If that same environment needs to be provisioned on new region, terraform skips the instance that user created from console. Because that instance is not managed by terraform. To avoid this, we have to import the instance to terraform.

Usage. Declare the instance on terraform file. resource "aws_instance" "name_of_the_instance" { ami = "" }

From the command line terraform import aws_instance.name_of_the_instance i-10dl10dl40dlsl

This command updates the terraform state file. Next time when the environment built it will create all the instance.