Uche-Questia: VARIABLE LIST

A VARIABLE LIST

A variable list uses a type of input variable that allows you to define a list of values using terraform configuration and it comes in handy when parameterizing. With a variable list terraform configuration uses "LIST" in the variable declaration.

https://www.blogger.com/blog/post/edit/5428112557550405099/2297842586278889989

HANDS-ON:

The below steps will identify how to deploy variable list. And list can be seen as passing a string ["d", "e", "f" ]. We need the instance, security group and variables.

STEP 1:

First: create a folder'variable-list' and within the folder create a file "provider.tf".

terraform {
  required_version = "1.3.4"
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = "4.39.0"
    }
  }
}

STEP 2:

Create a file "Variables.tf" and pass instance type variable as well as the count and list them as strings.

# dev instance ami id
variable "Dev-instance-ami-id" {
  type        = string
  default = "ami-0b0dc*****52a63"
}

# dev instance type
variable "Dev-instance-type" {
  type        = list(string)
  default = ["t2.micro" ,"t2.nano", "t2.large", "t2.small"]
}

# dev vpc cidr block
variable "Dev-vpc-cidrblock" {
  type        = string
  default = "10.0.0.0/16"
}

# dev vpc instance tenancy
variable "Dev-vpc-instance-tenency" {
  type        = string
  default = "default"
}

# dev subnet 1 cidr block
variable "Dev-subnet-1-cidrblock" {
  type        = string
  default = "10.0.1.0/24"
}

# dev subnet 1 availability zone
variable "Dev-subnet-1-availability-zone" {
  type        = string
  default = "us-east-1a"
}

# dev subnet 2 cidr block
variable "Dev-subnet-2-cidrblock" {
  type        = string
  default = "10.0.2.0/24"
}

# dev subnet 2 availability zone
variable "Dev-subnet-2-availability-zone" {
  type        = string
  default = "us-east-1b"
}
variable "provider-profile" {
  type = string
  default = "default"
}
  variable "dev-count" {
  description = "dev count"
  type = list(number)
  default = [1, 3, 5, 10]

}

STEP 3:

Create a file "ec2.tf" and pass the instance type and the count using the applicable "index" (0,1,2,.....n)

resource "aws_instance" "Development-VM" {
  ami           = var.Dev-instance-ami-id
  instance_type = var.Dev-instance-type[1]
  count = var.dev-count[0] # create four similar EC2 instances
  subnet_id = aws_subnet.Dev-subnet-1.id
  vpc_security_group_ids = [aws_security_group.Development-SG.id]
  tags = {
    Name = "Dev-VM"
  }
}

STEP 4:

We provisioned a "SG"

resource "aws_security_group" "Development-SG" {
  name        = "Development-SG"
  description = "Development Security Group"
  vpc_id      = aws_vpc.Dev-VPC.id

  ingress {
    description      = "TLS from VPC"
    from_port        = 80
    to_port          = 80
    protocol         = "tcp"
    cidr_blocks      = ["0.0.0.0/0"]
    ipv6_cidr_blocks = ["::/0"]
  }

### -1 protocol for egress means allow all traffic, and the below notation for ipv6 is the general way in which ipv6 is recognized.connection {

  egress {
    from_port        = 0
    to_port          = 0
    protocol         = "-1"
    cidr_blocks      = ["0.0.0.0/0"]
    ipv6_cidr_blocks = ["::/0"]
  }

  tags = {
    Name = "allow_http traffic"
  }
}

STEP 5:

Create a file called "Vpc-network.tf"

# Development VPC
resource "aws_vpc" "Dev-VPC" {
  cidr_block       = var.Dev-vpc-cidrblock
  instance_tenancy = var.Dev-vpc-instance-tenency

  tags = {
    Name = "Dev-VPC"
  }
}

# Development subnet 1
resource "aws_subnet" "Dev-subnet-1" {
  vpc_id     = aws_vpc.Dev-VPC.id
  cidr_block = var.Dev-subnet-1-cidrblock
  availability_zone = var.Dev-subnet-1-availability-zone
  tags = {
    Name = "Dev-subnet-1"
  }
}

# Development subnet 2
resource "aws_subnet" "Dev-subnet-2" {
  vpc_id     = aws_vpc.Dev-VPC.id
  cidr_block = var.Dev-subnet-2-cidrblock
  availability_zone = var.Dev-subnet-2-availability-zone
  tags = {
    Name = "Dev-subnet-2"
  }
}

# Development VPC internet Gateway
resource "aws_internet_gateway" "Dev-VPC-IGW" {
  vpc_id = aws_vpc.Dev-VPC.id

  tags = {
    Name = "Dev-VPC-IGW"
  }
}