terraform-aws-dynamic-subnets

what

• Remove usage of the region variable from documentation

why

• Historically region may have been a variable that could be passed to the terraform-aws-dynamic-subnets module, but currently it no longer is

what

• Properly pin providers in the example

why

• We don't use providers block to send providers to modules
• Use required_providers in terraform block to pin provider versions

and

provider "aws" {
  region = var.region
}

in top-level modules/examples to specify the region

what

• Use required_providers to pin Terraform providers

why

• Pinning the module's providers version in required_providers block allows specifying only the required provider version for the module without the need to specify all providers with versions explicitly

what

• Add bats and terratest for the example

why

• Better regression control
• Automatically test the example on every commit and pull request
• Provision resources on AWS in the test account and check the outputs for the correct values

what

• Update outputs

why

• Resources with counts are already lists in TF 0.12. Don't wrap them in [] (this creates a list of lists)

what

• Port (rewrite) module with 0.12 syntax
• Update Codefresh badge to point to the test pipeline in terraform-modules project
• Update examples
• Update README
• Update README examples

why

• Module currently does not work with 0.12
• Much easier syntax
• terraform-modules project contains pipelines for all terraform modules

what

• Update the label module to 0.11.1
• Use context

why

• Allows for fewer repeated variables
• Allows users of the label module to pass context into this module

what

• Add a variable for formatting the public/private subnet tags

why

• Formatting the subnet tags allows for use in more scenarios, such as when deploying spinnaker.io

what

• Add nat-instance
• Correctly pin terraform required_version

why

• Allow users to choose between NAT Gateways or NAT Instances to be deployed into the public subnets to allow the servers in the private subnets to access the Internet
• In many cases, NAT Instances are cheaper than NAT Gateways, and for some use-cases (e.g. testing/demo infrastructure) are more appropriate to use (e.g. save on cost)
• Pin terraform required_version to 0.11.x only (the module does not support TF 0.12

references

• https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-comparison.html
• https://docs.aws.amazon.com/vpc/latest/userguide/VPC_NAT_Instance.html
• https://dzone.com/articles/nat-instance-vs-nat-gateway

Include Availability Zone name in resource names and tags that are 1 per AZ (#46)

Include attributes in names and tags (#45)

what

• Add functionality for a VPC to auto-assign public IPs for instances

why

• It is a built-in function that makes sense to include in the module. A public VPC should assign Public IPs

what

• Remove route from aws_route_table for public subnets
• Add new resource aws_route

why

• Conflicts with other route table edits

what

• In private.tf, changed private_subnet_label so that name = "subnet" is now name = "${var.name}"

why

• Fix bug #39 to make the private and public subnet names consistent

what

• updated README.yaml file
• add tags and categories
• rebuild README.md file

why

• need to add categories and tags so we can pull them into the documentation

what

• Support use of tags by label modules

why

• Interoperability with all modules

what

• Add README.yaml

why

• Standardize README

what

• Allows the ability to override the max number of subnets to create.

why

For some regions with many availability zones the amount of subnets gets extreme. This allows the ability to override the max number of subnets to create. Still defaults to all if nothing is supplied.