AWS - SSH key generated by terraform

ssh_key_aws_terraform.tf

variable "key_name" {
  type    = string
  default = "manager_rsa"
}

# Creates a private key and saves it in Terraform state without encryption
# https://registry.terraform.io/providers/hashicorp/tls/latest/docs/resources/private_key
resource "tls_private_key" "rsa_key" {
  algorithm = "RSA"
  rsa_bits  = 4096
}

# Generate key pair for access EC2 instance 
# https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/key_pair
resource "aws_key_pair" "deployer" {
  key_name   = var.key_name
  public_key = tls_private_key.rsa_key.public_key_openssh
}

# https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance
resource "aws_instance" "web" {
  ...
  key_name = aws_key_pair.deployer.key_name
  ...
}

# In addition to having access by state, we can recover in other ways.
# Use output
output "private_ssh_key" {
  description = "ssh key generated by terraform"
  value       = tls_private_key.rsa_key.private_key_pem
}

# Use "local-exec" and create 'manager_rsa.pem' in current directory
resource "aws_key_pair" "deployer" {
  key_name   = var.key_name
  public_key = tls_private_key.rsa_key.public_key_openssh
  
  provisioner "local-exec" {
    command = "echo '${tls_private_key.rsa_key.private_key_pem}' > ./'${var.key_name}'.pem"
  }

  provisioner "local-exec" {
    command = "chmod 400 ./'${var.key_name}'.pem"
  }
}