create directory postgres and navigate
$ mkdir postgres && cd postgres
create main.tf file
$ vim main.tf

provider "aws" {
}
resource "aws_security_group" "rds_sg" {
  name = "rds_sg"
  ingress {
    from_port       = 5432
    to_port         = 5432
    protocol        = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_db_instance" "myinstance" {
  engine               = "postgres"
  identifier           = "myrdsinstance"
  allocated_storage    =  20
  engine_version       = "14"
  instance_class       = "db.t3.micro"
  username             = "myrdsuser"
  password             = "myrdspassword"
  parameter_group_name = "default.postgres14"
  vpc_security_group_ids = ["${aws_security_group.rds_sg.id}"]
  skip_final_snapshot  = true
  publicly_accessible =  true
}

output "rds_endpoint" {
  value = "${aws_db_instance.myinstance.endpoint}"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
Install postgres client in local machine
$ sudo apt install -y postgresql-client
To access AWS postgresql RDS instance
$ psql -h <end_point_URL> –p=5432 –username=myrdsuser –password –dbname=mydb
To destroy postgresql RDS instance
$ terraform destroy -auto-approve

create directory mysql and navigate
$ mkdir mysql && cd mysql
create main.tf
$ vim main.tf

provider "aws" {
}
resource "aws_security_group" "rds_sg" {
  name = "rds_sg"
  ingress {
    from_port       = 3306
    to_port         = 3306
    protocol        = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_db_instance" "myinstance" {
  engine               = "mysql"
  identifier           = "myrdsinstance"
  allocated_storage    =  20
  engine_version       = "5.7"
  instance_class       = "db.t2.micro"
  username             = "myrdsuser"
  password             = "myrdspassword"
  parameter_group_name = "default.mysql5.7"
  vpc_security_group_ids = ["${aws_security_group.rds_sg.id}"]
  skip_final_snapshot  = true
  publicly_accessible =  true
}

output "rds_endpoint" {
  value = "${aws_db_instance.myinstance.endpoint}"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
install mysql client in local host
$ sudo apt install mysql-client
To access the mysql
$ mysql -h <end_point_URL> -P 3306 -u <username> -p
To destroy the mysql RDS instance
$ terraform destroy -auto-approve

module "s3_bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"

  bucket = "kaniyam-bucket"
  acl    = "private"

  control_object_ownership = true
  object_ownership         = "ObjectWriter"

  versioning = {
    enabled = true
  }
}

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

resource "aws_s3_bucket" "example" {
  bucket = "example-my"
}

resource "aws_s3_bucket_ownership_controls" "ownership" {
  bucket = aws_s3_bucket.example.id
  rule {
    object_ownership = "BucketOwnerPreferred"
  }
}

resource "aws_s3_bucket_public_access_block" "pb" {
  bucket = aws_s3_bucket.example.id

  block_public_acls       = false
  block_public_policy     = false
  ignore_public_acls      = false
  restrict_public_buckets = false
}

resource "aws_s3_bucket_acl" "acl" {
  depends_on = [aws_s3_bucket_ownership_controls.ownership]
  bucket = aws_s3_bucket.example.id
  acl    = "private"
}

create directory s3-demo and navigate
$ mkdir s3-demo && cd s3-demo
create a demo file sample.txt and contents
$ echo “this is sample object to store in demo-bucket” > sample.txt
create main.tf file
$ vim main.tf

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

resource "aws_s3_bucket" "example" {
  bucket = "mydemo-bucket1"
}

resource "aws_s3_object" "object" {
  bucket = aws_s3_bucket.example.bucket
  key    = "sample.txt"
  source = "./sample.txt"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve

create directory s3 and navigate to the directory
$ mkdir s3 && cd s3
create main.tf file
$ vim main.tf

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

resource "aws_s3_bucket" "my_bucket" {
  bucket = "mydemo-bucket"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
To destroy the bucket
$ terraform destroy -auto-approve

create directory ec2 and navigate to the directory
$ mkdir ec2 && cd ec2
create main.tf file
$ vim main.tf

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

resource "aws_instance" "app_server" {
  ami = "ami-03f4878755434977f"
  instance_type = "t2.nano"
  subnet_id = "subnet-0ccba3b8cfd0645e2"
  key_name = "awskey"
  associate_public_ip_address = "true"
  tags = {
    Name = "demo-server"
  }
}

output "public_ip" {
  description = "public ip of the instance"
  value = aws_instance.app_server.public_ip
}

save and exit
initialize the terraform
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
it will create the AWS EC2 instance with output the public ip of the instance

To destroy the instance
$ terraform destroy -auto-approve

Method1: Package manager
$ wget -O- https://apt.releases.hashicorp.com/gpg | sudo gpg –dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg
$ echo “deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main” | sudo tee /etc/apt/sources.list.d/hashicorp.list
$ sudo apt update && sudo apt install terraform
$ terraform version
To get help options
$ terraform -h

Method2: Binary download
download the binary from wget https://developer.hashicorp.com/terraform/downloads
$ wget https://releases.hashicorp.com/terraform/1.6.6/terraform_1.6.6_linux_amd64.zip

extract using unzip
$ unzip terraform_1.6.6_linux_amd64.zip
$ mv terraform /usr/local/bin/
$ terraform version
$ terraform -h

To remove terraform binary method
$ sudo rm -f /usr/local/bin/terraform

To remove terraform package manager method
$ sudo apt remove terraform --purge