state-file-on-s3

Create a separate directory under the location you are working

# mkdir remote-state
# cd remote-state

#########
Step #1 - Create a .tf file that will create s3 bucket aws
#########

vim s3-setup.tf 
# with these contents
# ----- file s3-setup.tf STARTS here

resource "aws_s3_bucket" "terraform-state-storage-s3" {
  bucket = "networknuts-terraform-state-s3"
  region = "ap-south-1"

  versioning {
    # enable with caution, makes deleting S3 buckets tricky
    enabled = false
  }

  lifecycle {
    prevent_destroy = true
  }

  tags = {
    name = "S3 Remote Terraform State Store"
    proj = "networknuts"
    env = "prod"
  }
}

# create a DynamoDB table for locking the state file
resource "aws_dynamodb_table" "dynamodb-terraform-state-lock" {
  name = "networknuts-iac-terraform-state-lock-dynamo"
  hash_key = "LockID"
  read_capacity = 20
  write_capacity = 20

  attribute {
    name = "LockID"
    type = "S"
  }

  tags = {
    name = "DynamoDB Terraform State Lock Table"
    proj = "networknuts"
    env = "prod"
  }
}

# --- file s3-setup.tf ENDS here

Run: 
# terraform plan
# terraform init
# terraform apply

#########
Step #2 - Create a file state-location.tf, which will change state file location from local to s3
#########

vim state-location.tf
# --- file state-location.tf STARTS here

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

# store tfstate in s3 and locking information in DynamoDB
terraform {
  backend "s3" {
    encrypt = true
    # cannot contain interpolations
    bucket = "networknuts-terraform-state-s3"
    region = "ap-south-1"
#first run terraform init and terraform apply with comment against dynamodb_table 
#then run it again after removing the comment
    #dynamodb_table = "networknuts-iac-terraform-state-lock-dynamo"
    key = "terraform-state/terraform.tfstate"
  }
}

# --- file state-location.tf ENDS here

Run:
# terraform plan
# terraform init
# terraform apply
# --- now go and uncomment the dynanodb_table line 
Run:
# terraform plan
# terraform init
# terraform apply


#########
Step #3 - Create a resource and check the .tfstate file on AWS S3
#########
vim webserver.tf

# --- file webserver.tf STARTS here

resource "aws_instance" "webserver" {
  ami           = "ami-0b5bff6d9495eff69"
  instance_type = "t2.micro"
  tags = {
    Owner = "serverterra"
  }

}

# --- file webserver.tf ENDS here

Run:
# terraform plan
# terraform init (if prompted)
# terraform apply

#GO TO AWS dashboard and check .tfstate file