rajiska/terraform-aws-fck-nat

Terraform module for fck-nat

terraform-aws-fck-nat's Issues

The repository doesn't match the existing Terraform module

@RaJiska, the repository shows use of multiple route tables using route_tables_id (what I wish to use), but the Terraform module is still using the deprecated version.

When will this be updated?

Compatibilty with cloudposse

is it possible to make it compatible with cloudposse/terraform-aws-dynamic-subnets

Current state?

Hi,

Thank you for this project. I arrived here from a link in a issue in the fck-nat repository.

I was wondering if this is ok to deploy or is it still at a development stage.

I'm not asking if it's production grade. I'm working on a personal project and the managed NAT cost is not sustainable. Most likely I'll switch back to the managed NAT by the time/if I hit production.

So I just need this to be stable enough not to think about it.

Thanks =)

Question: why two private IPv4 addresses?

Hi,

I've set up and am using fck-nat via the Terraform module. My module config looks like this:

  module "fck-nat" {
  source = "git::https://github.com/RaJiska/terraform-aws-fck-nat.git?ref=ab69ccf34629e49033f52c4e6351e188be7a1f8f"

  name      = "${local.label}-fck-nat"
  vpc_id    = aws_vpc.vpc.id
  subnet_id = aws_subnet.public_subnet01.id
  ha_mode   = false # Enables high-availability mode
  #  eip_allocation_ids = ["eipalloc-0137b6eb9d101f063"] # Allocation ID of an existing EIP / see https://github.com/RaJiska/terraform-aws-fck-nat/issues/5
  instance_type = var.instance_type

  update_route_tables = true
  route_tables_ids = {
    "private_rt" = aws_route_table.private_rt.id
  }

  tags = {
    Name = "${local.label}-fck-nat"
  }

  # To ensure proper ordering, add an explicit dependency on the Internet Gateway for the VPC.
  depends_on = [aws_internet_gateway.igw]
}

and I end up with two private IPv4 addresses against the instance:

and I'm not sure why. I don't think it's part of the AMI (tested by starting an instance with the AMI and I got only one private IPv4 address) and I've glanced (not studied) the module's Terraform config where it wasn't immediately obvious to me why two private IPv4 addresses are assigned.

Is there a reason why there are two IPv4 addresses assigned to the fck-nat instance when using the Terraform module?

Regards,

Warren.

var.additional_security_group_ids not in use by the module

Just a heads up that var.additional_security_group_ids is not being used by the aws_network_interface resource.

A visible fix is to point security_groups = [aws_security_group.main.id] to security_groups = local.security_groups

Great work with the module!

Can fck-nat be configured to serve as a private nat?

Hello,

Thanks for the great initiative of fck-nat terraform module!

I was looking into possibly using fck-nat for the purpose of private nat, without an external public IP, but noticed this terraform module is hardcoded to add a public IP address https://github.com/RaJiska/terraform-aws-fck-nat/blob/main/ec2.tf#L59

Would it be easy to make it configurable for private nat?

Thanks

Architecture

Hello, I'm new to nat instances.

Is the intention with this module, to have 1 module per subnet/AZ in a VPC?

I notice the variables for route table ID's and subnet id's are of type string, and not list. So im thinking i'd need one fck-nat per AZ?

For the HA option - is that HA in the single AZ?

Attaching the same elastic IP not working

Hello and thank you for developing this module! I'm trying to pass eip_allocation_ids so that the NAT instance always has the same public IP but it's not working. I don't see the elastic IPs being associated with the EC2 instances. Here's an example configuration:

resource "aws_eip" "nat" {
  count = length(var.external_subnets)
  vpc   = true
}

module "fck-nat" {
  count = length(var.external_subnets)

  source  = "RaJiska/fck-nat/aws"
  version = "1.2.0"

  name                 = "fck-nat-${count.index}"
  vpc_id               = aws_vpc.main.id
  subnet_id            = element(aws_subnet.external.*.id, count.index)
  
  ami_id               = "ami-00d653f185e930c04"
  instance_type        = "t4g.nano"
  use_spot_instances   = false
  use_cloudwatch_agent = true
  encryption           = true
  update_route_table   = true
  route_table_id       = element(aws_route_table.internal.*.id, count.index)
  ha_mode              = true
  eip_allocation_ids   = [element(aws_eip.nat.*.id, count.index)]
}

I see that the allocation_id is passed in the user data as eip_id=... but for some reason it is not associated with the EC2 as it should be happening here. I tried viewing logs from inside the instance with aws ec2 get-console-output --instance-id ... but didn't have much success as no logs were shown. I'm wondering whether I need to change my configuration to something like

resource "aws_eip" "nat" {
  count = length(var.external_subnets)
  vpc   = true
  network_interface = element(fck-nat.*.eni_id, count.index)
}

which would associate the Elastic IP with the Network Interface but then I'm not sure why this call should be made at all. As a matter of fact, I'm also wondering about those calls as well since the network interface is already attached to the EC2. Maybe there's no need to pass eni_id and eip_id if the infrastructure is already configured (eip and eni attached)? That would also remove the need for the IAM permissions.

Another eip related thing I'm wondering about is this one. Do you think that if eip_allocation_ids is provided there's no need to create an ephemeral public network interface since there's already an elastic IP that will be associated with this instance?

update_route_tables and route_tables_ids error with Unexpected Attribute

When trying to use fck-nat as a module in terraform, documentation says that update_route_table and route_table_id is deprecated. However, the recommended variables update_route_tables and route_tables_ids errors out as Unexpected Attribute.

module "fck-nat" {
  source = "RaJiska/fck-nat/aws"
  name = "fck-nat-${var.availability_zones[count.index]}"
  vpc_id = aws_vpc.main.id
  subnet_id = aws_subnet.public[count.index].id
  use_spot_instances = true
  instance_type = "t4g.nano"
  update_route_tables = true
  route_tables_ids = {
    "private" = aws_route_table.private[count.index].id
  }
}

Allow to use non-arm instances

Hi. I'm trying to run this module with t2.micro, and I can't use it b/c of the wrong (?) arm regex checker. I'm not a master of regex, but for me, it looks a little bit wrong. I was trying to use regex101 but found redundant backslashes.
[a-zA-Z]+\\d+g[a-z]*\\..+ should be [a-zA-Z]+\d+g[a-z]*\..+

╷
│ Error: Error in function call
│
│   on .terraform/modules/fck-nat/main.tf line 2, in locals:
│    2:   is_arm             = regex("[a-zA-Z]+\\d+g[a-z]*\\..+", var.instance_type) == var.instance_type
│     ├────────────────
│     │ while calling regex(pattern, string)
│     │ var.instance_type is "t2.micro"
│
│ Call to function "regex" failed: pattern did not match any part of the given string.

Exclude name from passed tags for asg or check that it's not provided

  tag {
    key                 = "Name"
    value               = var.name
    propagate_at_launch = true
  }

  dynamic "tag" {
    for_each = var.tags

    content {
      key                 = tag.key
      value               = tag.value
      propagate_at_launch = false
    }

It will be good to check here that Name tag is not in the provided map and apply it only if it's not there