AWS Security Group not in VPC error with Terraform

Question

To make a long story short, using Terraform, I want to

Create a VM in AWS
Have the VM in a security group that allows port 80, 443 and 22.

Accomplishing item 1 was straightforward. To accomplish item 2 I understood that:

I needed to create a VPC first. This worked.
I then needed a subnet inside the vpc. This worked.
I then needed to create the security groups associated with the VPC. This worked.
I then needed to add the VPC security group ids to my aws_instance. THIS LINE CAUSES IT TO FAIL. vpc_security_group_ids = ["${aws_security_group.allow_ssh.id},${aws_security_group.allow_web.id}"]

I have the following Terraform plan:

# Provider Details
provider "aws" {
  region                  = "us-east-1"
  shared_credentials_file = "/Users/default/.aws/credentials"
  profile                 = "my-profile"
}

# Main VPC
resource "aws_vpc" "vpc_main" {
  cidr_block = "10.0.0.0/16"

  enable_dns_support   = true
  enable_dns_hostnames = true

  tags {
    Name = "Main VPC"
  }
}

resource "aws_subnet" "public" {
  vpc_id                  = "${aws_vpc.vpc_main.id}"
  cidr_block              = "10.0.0.1/16" 
  map_public_ip_on_launch = true
  tags {
    Name                  = "Public Subnet"
  }
}

resource "aws_security_group" "allow_web" {
  name        = "allow-web-traffic"
  description = "Allow all inbound/outbound traffic on 80 443"
  vpc_id      = "${aws_vpc.vpc_main.id}"

  ingress {
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  ingress {
    from_port = 443
    to_port   = 443
    protocol  = "tcp"
  }

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

resource "aws_security_group" "allow_ssh" {
  name        = "allow-ssh-traffic"
  description = "Allow ssh traffic on 22"
  vpc_id      = "${aws_vpc.vpc_main.id}"

  ingress {
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

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

resource "aws_instance" "proxy_server" {
  ami           = "ami-6871a115" # RHEL 7.5 HVM SSD
  instance_type = "t2.micro"     
  key_name      = "cwood_sa"
  vpc_security_group_ids = ["${aws_security_group.allow_ssh.id},${aws_security_group.allow_web.id}"] # this breaks it
  subnet_id     = "${aws_subnet.public.id}"      
}

The resulting error.

* aws_instance.proxy_server: Error launching source instance: InvalidGroup.NotFound: The security group 'sg-063c2b4b4836f18aa,sg-07e562845b70bf125' does not exist in VPC 'vpc-0397460a8f633574c'
status code: 400, request id: dae8b8e8-8259-4ef1-b9c2-a8b782f96235

But if I look in the AWS Console, those security groups are associated with the VPC.

I'm assuming I'm making a fundamental error here somewhere and need some help.

micarlise micarlise · Accepted Answer · 2018-08-30T21:02:58

Each security group needs to be surrounded by quotes. You currently have the line:

vpc_security_group_ids = ["${aws_security_groups.allow_ssh.id},${aws_security_group.allow_web.id}"]

this is not valid HCL list syntax . Update your security group line to:

vpc_security_group_ids = ["${aws_security_groups.allow_ssh.id}","${aws_security_group.allow_web.id}"]

AWS Security Group not in VPC error with Terraform

1 Answers