The document discusses Terraform 0.13, highlighting module improvements, enhancements in the provider ecosystem, and breaking changes. It outlines the evolution of Terraform from previous versions and details the benefits of new features like custom variable validation and improved dependency management. The author concludes with insights into potential future developments and resources for further learning.

2. TERRAFORM 0.13:
RISE OF THE MODULES_
Marko Bevc

3. BUILDING
BLOCKS_
“Abstraction of common blocks of
configuration into a reusable
infrastructure elements.”
— @sheriffjackson, 2018 blog
DRY code – Don’t Repeat Yourself
Everything is a module!

4. ABOUT
ME_ ●
Senior IT Consultant at The Scale Factory (DevOps consultancy,
AWS advanced consulting partner and K8s service provider)
●
IT system engineering and design background with extensive
Linux and virtualization experience
●
Certifications and competencies: AWS, CKA, RHEL, Hashi stack
●
Open source contributor and supporter
●
Fan of automation/simplifying things, hiking, cycling and travelling

5. TOPICS
COVERED_
●
Terraform time line
●
Module improvements
●
Provider ecosystem
●
Other enhancements and breaking
changes
●
How to get started and a demo
●
Conclusions and path forward

6. TERRAFORM
TIME LINE_
• Pre-v0.10 era (provisioners, state ENV, remote
state and locking)
• Period v0.10 – v0.11 (workspaces, core/provider
split, TF registry (private), module providers,
streamlined APPLY)
• Big changes with v0.12 (HCL2: 1st
class
expressions, gen.types, iterations/dyn.blocks,
structural plans and better error messages)
• Module and provider improvements in v0.13
HISTORY
2014 (initial v0.1.0) 2020 (v0.13) v0.14..1.0*2017 (v0.9-0.11) 2019 (v0.12)

7. MODULE
EXPANSION_
●
Improved module usability and functionality
●
Create multiple instances of a module from a single
module block:
– count (tuple/list)
– for_each (map)
●
Simplified configuration logic and better automation
●
Can create some indirect module-level dependencies
●
Cannot use provider blocks per module instance! *
(i.e. AWS regions)

8. locals {
resources = {
prod = "prod-eks"
qa = "qa-eks"
dev = "dev-eks"
}
}
module "eks" {
source = "terraform-aws-modules/eks/aws"
for_each = local.resources
cluster_name = each.value
cluster_version = "1.17"
subnets = ["subnet-abcde012", "subnet-bcde012a", "subnet-fghi345a"]
vpc_id = "vpc-1234556abcdef"
worker_groups = [
{
name = each.key
instance_type = "m4.large"
asg_max_size = 3
}
]
}
eks-clusters.tf

9. MODULE
DEPENDENCIES_
• Dependencies types:
– implicit
– explicit
• Previously module instances were NOT nodes in dependency graph
(just separate namespaces, dependencies via I/O values)
• depends_on meta-argument ensures order of module resource
changes – create after any dependent resource changes have been
applied
• Far more coarse declaration of dependency than encouraged – last
resort! (*auto deps: easier to maintain and maximise concurrency)

10. resource "aws_iam_policy_attachment" "example" {
name = "example"
roles = [aws_iam_role.example.name]
policy_arn = aws_iam_policy.example.arn
}
module "uses-role" {
# ...
depends_on = [aws_iam_policy_attachment.example]
}

11. PROVIDER
ECOSYSTEM_
• Improvements to Terraform Provider Registry
• Automatic install of 3rd
party providers
• Provider source block with namespace separation, defaults to
HashiCorp’s providers: [registry.terraform.io/][hashicorp/]type
• One provider per module, but nesting not recommended!
• Simplifying the installation of community providers:
– Official HashiCorp supported providers
– Partner-supported providers (needs required_providers now)
– Locally installed providers (3rd
party provider plugins):
./plugins/example.com/myorg/customplugin/0.1/linux_amd64/

12. OTHER
ENHANCEMENTS_
●
Custom variable validation rules (experimental since
v0.12, zero or more rules)
●
Terraform Cloud streamlined authentication process
(terraform login connects CLI to TF Cloud)
●
Providers mirror (terraform providers mirror)
●
Terraform CLI supports TLS 1.3
●
Breaking changes:
– Source for non-default providers
– Locking was improved and changes to the
TableStore schema now require a primary key
named LockID of type String
– macOS builds of Terraform CLI are no longer
compatible with macOS 10.10 Yosemite
– Terraform CLI now requires FreeBSD 11.2 or later.

13. variable "image_id" {
type = string
description = "The id of the machine image (AMI) to use for the server."
validation {
# regex(...) fails if it cannot find a match
condition = can(regex("^ami-", var.image_id))
error_message = "The image_id value must be a valid AMI id, starting
with "ami-"."
}
}
# NOT needed anymore
terraform {
experiments = [variable_validation]
}
Variable custom validation rules

14. HOW TO
GET STARTED_
●
Get binary from: releases.hashicorp.com
●
Ensure no pending configuration changes
●
Versioning or backup of code
●
Data resource reads can no longer be disabled - deps
●
Destroy-time provisioners cannot refer to other
resources – deprecated
●
New hierarchical namespace - explicit source for any
not HashiCorp-maintained providers
●
New directory structure for manually-installed
providers
●
terraform 0.13upgrade (gradual one release jumps)
●
Follow CHANGELOG for more details

15. TIME FOR
DEMO!_

16. CONCLUSIONS_
& TAKEAWAYS
●
Module improvements: expansion (count, for_each) and
dependencies
●
Provider source and hierarchical namespace – wider ecosystem
and required source, terraform mirror to avoid re-download
●
Custom validation rules for input variables
●
Streamlined Terraform Cloud auth CLI process
●
Improved state locking and schema changes
●
v0.14 (path to v1.0): possible features(CLI/Cloud parity, sensitive
values, import, module testing)

17. ●
Resources:
– https://www.scalefactory.com/blog/2020/06/25/what-we-are-looking-forward-to-in-terraform-
0.13/
– https://www.hashicorp.com/blog/announcing-the-terraform-0-13-beta/
– https://www.hashicorp.com/blog/custom-variable-validation-in-terraform-0-13/
– https://www.terraform.io/docs/configuration/syntax.html
– https://www.hashicorp.com/blog/hashicorp-terraform-modules-as-building-blocks-for/
– https://www.hashicorp.com/resources/the-path-to-terraform-1-0/
– https://www.hashicorp.com/blog/announcing-terraform-0-12/
– https://en.wikipedia.org/wiki/Don%27t_repeat_yourself
FURTHER
READING_

18. KEEP IN
TOUCH_
https://www.scalefactory.com/
@_MarkoB
@mbevc1
@mbevc1
https://www.linkedin.com/in/marko-bevc/
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