I have code to create VPC, with 2 private subnets, 2xec2 instances in private and bastion in public.
ec2 code uses outputs.tf of VPC module subnet_ids. as there are 2 private subnets there are 2 subnet_ids being generated. when these generated subnet_ids are fed into ec2 instances instead of one subnet_id, it is feeding 2 subnet_ids at once as a single value.
As a result terraform couldn't find that subnet_ids value, creation is being failed.
error: The subnet ID 'subnet-0***********,subnet-0*************' does not exist
editing subnets* vpc.tf
private_subnets = "10.10.20.#/#,10.10.20.#/#"
instanceec2.tf
subnet_id = "${module.vpc.private_subnets}"
below are modules:
vpc_main.tf
// Private subnet/s
resource "aws_subnet" "private" {
vpc_id = "${aws_vpc.vpc.id}"
cidr_block = "${element(split(",", var.private_subnets), count.index)}"
availability_zone = "${element(split(",", var.azs), count.index)}"
count = "${length(split(",", var.private_subnets))}"
tags {
Name = "${var.name}-private-${element(split(",", var.azs), count.index)}"
Team = "${var.team}"
Environment = "${var.environment}"
Service = "${var.service}"
Product = "${var.product}"
Owner = "${var.owner}"
Description = "${var.description}"
managed_by = "terraform"
}
}
resource "aws_route_table" "private" {
vpc_id = "${aws_vpc.vpc.id}"
count = "${length(split(",", var.private_subnets))}"
tags {
Name = "${var.name}-private-${element(split(",", var.azs), count.index)}"
Team = "${var.team}"
Environment = "${var.environment}"
Service = "${var.service}"
Product = "${var.product}"
Owner = "${var.owner}"
Description = "${var.description}"
managed_by = "terraform"
}
}
resource "aws_route_table_association" "private" {
subnet_id = "${element(aws_subnet.private.*.id, count.index)}"
route_table_id = "${element(aws_route_table.private.*.id, count.index)}"
count = "${length(split(",", var.private_subnets))}"
}
``````
vpc_outputs.tf
```````
output "private_subnets" {
value = "${join(",", aws_subnet.private.*.id)}"
}
Expected value is only one subnet ID as value:
Error: supply 2 Subnet IDs as one value.
aws_instance.ec2-instance[0]: 1 error(s) occurred:
- aws_instance.ec2-instance.0: Error launching source instance: InvalidSubnetID.NotFound: The subnet ID 'subnet-0**********,subnet-0***********' does not exist