Sample resources for instance in terraform declared only by resources

instance-by-resources.tf

data "template_file" "user_data" {
  template = file("cloudinit/addpubkey.yml")
}

resource "aws_vpc" "mainvpc" {
  cidr_block = "10.1.0.0/16"
}

resource "aws_internet_gateway" "gw" {
  vpc_id = aws_vpc.mainvpc.id
}

resource "aws_subnet" "default" {
  vpc_id = aws_vpc.mainvpc.id
  cidr_block = "10.1.0.0/24"
}

resource "aws_route_table" "main_rt" {
  vpc_id = aws_vpc.mainvpc.id
  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.gw.id
  }
}

resource "aws_security_group" "main_sg" {
  vpc_id = aws_vpc.mainvpc.id
  egress {
    from_port = 0
    to_port = 0
    protocol = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  } 
  ingress {
    from_port = 0
    to_port = 0
    protocol = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_key_pair" "deployer" {
  key_name = "deployer-key"
  public_key = "ssh-rsa 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 dxv1d@fedora"
}

resource "aws_instance" "registry" {
  ami = "ami-0d4702e961515ac94"
  instance_type = "t2.micro"
  associate_public_ip_address = true 
  subnet_id = aws_subnet.default.id 
  key_name = aws_key_pair.deployer.key_name
  # user_data = data.template_file.user_data.rendered 
  vpc_security_group_ids = [aws_security_group.main_sg.id]
  # security_groups = ["anything"] 
}