Terraform | AWS | vpc_id causing apply to fail

Question

I am working on setting up a Cloud9 environment using Terraform, I ran into an issue when it comes to my Terraform apply and specifically:

Error: Error applying plan:

1 error(s) occurred:

* aws_instance.cloud9Test: 1 error(s) occurred:

* aws_instance.cloud9Test: Error launching instance, possible mismatch of Security Group IDs and Names. See AWS Instance docs here: https://terraform.io/docs/providers/aws/r/instance.html.
        AWS Error: Value () for parameter groupId is invalid. The value cannot be empty

Here is my Terraform code that seems to be related and causing the issue.

resource "aws_vpc" "cloud9Test" {
  cidr_block       = "10.0.0.0/16"
  instance_tenancy = "dedicated"

  tags = {
    Name = "cloud9Test"
  }
}

resource "aws_security_group" "cloud9Test" {
    name = "cloud9Test-sg"
    description = "Cloud9 Group"
    vpc_id      = "${aws_vpc.cloud9Test.id}"
}

When I comment out the vpc_id in the security group I don't have the issue anymore but I do want the security group inside my VPC.

How do I fix this?

Note I do not have anything that should overlap causing an issue, this is a fairly new account with only 3 ec2 instances and 1 cloud9 instance all created manually

Answer 1

I'll go out on a limb here and assume that the issue is actually in your "aws_instance" block and is likely the result of how you are assigning the security groups in the "aws_instance".

Copied from the first linked article, in the resolution:

change 

security_groups = ["cloud9Test"]

to

vpc_security_group_ids = ["${aws_security_group.cloud9Test.id}"]

Two related articles:

https://github.com/KainosSoftwareLtd/aws-api-gateway-demo/issues/3

https://stackoverflow.com/questions/31569910/terraform-throws-groupname-cannot-be-used-with-the-parameter-subnet-or-vpc-se/34586893#34586893

If this is not on track, please post the "aws_instance" declaration.

For your own sanity I'd also recommend giving the resources names that are more specific to their role, and not identical, for example "cloud9Test_vpc".