Terraform 0.12 Deep Dive: HCL 2.0 for Infrastructure as Code, Remote Plan & Apply

© 2018 HashiCorp
An infrastructure as code approach to safely
provision any cloud, infrastructure, or service.
Multi cloud.
Hybrid cloud.
Any infrastructure.
Anywhere.
1

Copyright © 2018 HashiCorp ⁄ 2
Arslan Saeed
Senior Solutions Engineer
HashiCorp
Kristin Laemmert
Software Engineer
HashiCorp
Twitter: @mildwonkey
Our Presenters
Today

© 2018 HashiCorp
Terraform 0.12:
HCL Enhancements &
Remote Plan & Apply
3

Copyright © 2018 HashiCorp ⁄
Introduction to Terraform
● Infrastructure as code
● Workflow
● Providers
Terraform 0.12
● HCL Enhancements
● Remote Plan & Apply
Terraform Enterprise
● Overview
● Demo
4
Agenda
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2
3

© 2018 HashiCorp
Introduction to
Terraform
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Networking
Connect infrastructure and
applications
Development
Run applications
Security
Secure applications and
infrastructure
Operations
Provision Infrastructure
The 4 essential
elements of
dynamic
infrastructure
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© 2018 HashiCorp
Networking
Connect infrastructure and
applications
Development
Run applications
Security
Secure applications and
infrastructure
Operations
Provision Infrastructure
The 4 essential
elements of
dynamic
infrastructure
7

© 2018 HashiCorp
Static Infrastructure
Homogeneous, Private
The shift to
provisioning
dynamic
infrastructure
Dynamic Infrastructure
Heterogeneous, Distributed
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The shift to
provisioning
dynamic
infrastructure
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The shift to
provisioning
dynamic
infrastructure
Relies on static fleet of standardized
infrastructure, provisioned for long periods
of time, and dedicated to users.
Traditional Approach
▪ Manual provisioning
▪ Fixed set of resources
▪ Workflows require ticketing & queues
Heterogeneous infrastructure, frequently
provisioned, short lived, and automated
provisioning on-demand.
Terraform Approach
▪ Infrastructure as code
▪ Embrace diversity with providers
▪ Enable self-service infrastructure
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Terraform
Principles
Infrastructure as
code
Codification allows
infrastructure changes to be
automated, while keeping the
definition human readable.
Automated tooling allows
operators to increase their
productivity, move quicker, and
reduce human error.
11Copyright © 2018 HashiCorp ⁄
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Terraform
Principles
Workflows, not
Technology
Terraform does not abstract the
underlying providers, instead
allowing users to leverage the
differentiating features with a
consistent workflow. As new
technologies emerge, they can
be adopted without changing
the provisioning workflow:
plan to preview changes and
apply to make changes to any
infrastructure globally.
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Terraform
Principles
Open and Extensible
Terraform works with over 160
different providers for a broad
set of common infrastructure.
Provider SDK makes it simple to
create new and custom
providers.
Providers leverage
infrastructure-specific APIs to
preserve unique capabilities for
each provider.
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150+

© 2018 HashiCorp
How It Works: Workflow
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Terraform
Use Cases
Adopt any cloud,
infrastructure, or service
safely, efficiently, and
timely.
Multi-Cloud
Management
Provision and manage public
cloud, private infrastructure,
and external services
holistically while still
preserving the uniqueness of
each.
Self-Service
Infrastructure
Provide a library of approved
infrastructure that developers
can use to safely and
efficiently provision
infrastructure on-demand.
Infrastructure
as Code
Use infrastructure as code to
safely and efficiently
provision and manage
infrastructure at any scale.

© 2018 HashiCorp
Terraform 0.12
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HCL Enhancements
Introduction to HCL
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Terraform
Configuration
Language:
Terraform 0.11
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● HCL: HashiCorp Configuration Language
● HIL: HashiCorp Interpolation Language
${ }
● Terraform-native variables and functions
# An AMI
variable "ami" {
description = "the AMI to use"
}
/* A multi line comment. */
resource "aws_instance" "web" {
ami = "${var.ami}"
count = 2
source_dest_check = false
connection {
user = "root"
}
}

© 2018 HashiCorp
Terraform
Configuration
Language:
Terraform 0.12
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Enhanced HCL
● Merges HCL and HIL
● Introduces a robust type system
● Addresses large list of enhancements and feature
requests

© 2018 HashiCorp
Terraform 0.12:
Configuration
Language
Enhancements
20
● First Class Expressions
● For Expressions
● Dynamic Blocks
● Conditional Improvements
● Rich Types in Module inputs & outputs
● Improved Error Messages
● Template Syntax
● Reliable JSON Syntax

© 2018 HashiCorp
HCL Enhancements Deep Dive
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HCL Enhancements
First Class Expressions
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Terraform 0.12:
First-Class
Expressions
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● Operations and variables can be used outside
of string interpolation
○ Buh-bye “${ }”
● Lists and maps can be used directly with
expressions
○ Less list(""), more []

CODE EDITOR
© 2018 HashiCorp
variable "ami" {}
variable "instance_type" {}
variable "vpc_security_group_ids" {
type = "list"
}
resource "aws_instance" "example" {
ami = "${var.ami}"
instance_type = "${var.instance_type}"
vpc_security_group_ids = "${var.vpc_security_group_ids}"
}
Terraform 0.11
main.tf
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CODE EDITOR
© 2018 HashiCorp
variable "ami" {}
type = list(string)
}
ami = var.ami
instance_type = var.instance_type
vpc_security_group_ids = var.vpc_security_group_ids
}
Terraform 0.12
main.tf
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CODE EDITOR
© 2018 HashiCorp
variable "ami" {}
type = "string"
default = ""
}
ami = "${var.ami}"
instance_type = "${var.instance_type}"
vpc_security_group_ids =
"${var.vpc_security_group_id != "" ?
[var.vpc_security_group_id] : list("") }"
}
Terraform 0.11
main.tf
26

CODE EDITOR
© 2018 HashiCorp
variable "ami" {}
type = string
default = ""
}
ami = var.ami
instance_type = var.instance_type
vpc_security_group_ids =
var.vpc_security_group_id != "" ?
[var.vpc_security_group_id] : []
}
Terraform 0.12
main.tf
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© 2018 HashiCorp
Terraform 0.12
Rich Value Types
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Rich Value
Types
● Enhances simple type system
● Complex values
○ maps and lists!
○ maps of maps!!
○ maps of lists of maps of lists!!!
● Entire resources and modules as values
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TERMINAL
© 2018 HashiCorp
$ tree
.
├── main.tf
├── terraform.tfvars
└── modules
└── subnets
└── subnets.tf
Terraform
Module
Layout
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CODE EDITOR
© 2018 HashiCorp
variable "networks" {
type = "list"
}
module "subnets" {
source = "./modules/subnets"
networks = "${var.networks}"
...
}
output "vpc_id" {
value = "${module.subnets.aws_vpc.example.id}"
}
Terraform 0.11
main.tf
31

CODE EDITOR
© 2018 HashiCorp
// "subnets" module
type = "list"
}
resource "aws_vpc" "example" {
networks = "${var.networks}"
...
}
output "vpc_id" {
value = "${aws_vpc.example.id}"
}
output "vpc_az" {
value = "${aws_vpc.example.availability_zone}"
}
Terraform 0.11
subnets.tf
32

CODE EDITOR
© 2018 HashiCorp
type = map(object({
network_number = number
availability_zone = string
tags = map(string)
}))
}
module "subnets" {
networks = var.networks
}
output "vpc_id" {
value = module.subnets.aws_vpc.example.id
}
Terraform 0.12
main.tf
33

CODE EDITOR
© 2018 HashiCorp
networks = {
"production" = {
network_number = 1
availability_zone = "us-east-1a"
}
"staging" = {
network_number = 2
availability_zone = "us-east-1a"
}
}
Terraform 0.12
terraform.tfvars
34

CODE EDITOR
© 2018 HashiCorp
// "subnets" module
type = map(object({
tags = map(string)
}))
}
resource "aws_vpc" "example" {
...
}
output "vpc" {
value = aws_vpc.example
}
Terraform 0.12
subnets.tf
35

CODE EDITOR
© 2018 HashiCorp
type = map(object({
tags = map(string)
}))
}
module "subnets" {
}
resource "aws_instance" "my_server" {
subnet_id = module.subnets.aws_vpc.example.id
az = module.subnets.aws_vpc.example.availability_zone
...
}
Terraform 0.12
main.tf
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© 2018 HashiCorp
Terraform 0.12
Improved Error Messages
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TERMINAL
© 2018 HashiCorp
$ terraform plan
Error: Error parsing main.tf: object expected
closing RBRACE got: EOFTerraform 0.11
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TERMINAL
© 2018 HashiCorp
$ terraform plan
Error: Argument or block definition required
on main.tf line 24:
24: :wq
An argument or block definition is required here.
Terraform 0.12
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TERMINAL
© 2018 HashiCorp
$ terraform plan
Error: Invalid operand
on main.tf line 16, in output "foobar":
16: value = "${1 + var.foo}"
Unsuitable value for right operand: a number is
required.
Terraform 0.12
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TERMINAL
© 2018 HashiCorp
$ terraform plan
Error: Unsupported block type
on main.tf line 36, in outptu "item":
1: outptu "item" {
Blocks of type "outptu" are not expected here. Did
you mean "output"?
Terraform 0.12
41

More about
Terraform
0.12
Please read our Terraform 0.12 Blog for more
information.
https://www.hashicorp.com/blog/terraform-0-1-2-preview
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Upgrade Please read our Terraform 0.12 Upgrade Guide:
https://www.terraform.io/upgrade-guides/0-12.html
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© 2018 HashiCorp
Remote Plan
and Apply
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● Ability to utilize Terraform functions ie ‘plan’ and
‘apply’ back-ended and executed by Terraform
Enterprise remotely
● Centralized within Terraform Enterprise
● View of change history
● Ability to integrate policy controls and checks

© 2018 HashiCorp
How It Works: Usage
50
terraform {
backend "remote" {
organization =
"my-org"
workspaces {
prefix =
"networking-"
}
}
}
> terraform init > terraform plan
> terraform apply
Add the remote
backend config
Migrate state
Plan and Apply, just
like before
1) Set “backend” to “remote”
2) Set “organization” to TFE org name
3) Set prefix as selector of workspaces
4) Add your token to your home
directory
Updates configuration to use new
backend. Migrates state to TFE from
previous (local, S3, etc)
Anywhere TF used the plan and apply
will work as-is. CI/CD will work with little
or no modification.

Terraform Enterprise

Demo

© 2018 HashiCorp
HCL
Enhancements
Terraform
Guides
55HCL ENHANCEMENTS
Latest Alpha
Release
https://releases.hashicorp.com/terraform/0.12.0
-alpha4/
Terraform 0.12 Examples
https://bit.ly/2SI0ElE
https://github.com/hashicorp/terraform-guides/tree/
master/infrastructure-as-code/terraform-0.12-exam
ples

www.hashicorp.com
hello@hashicorp.com
Thank you
58

Copyright © 2017 HashiCorp 59
How it works
First Class Expressions
With 0.12, expressions are a native part of the
language and can be used directly.
Read more
Easier to Read/Write/learn
Rich Types in Module Inputs and Outputs
Terraform 0.12 allows arbitrarily complex lists and
maps for any inputs and outputs, including with
modules and resources. Read More
Reliable JSON Syntax
Terraform 0.12 HCL configuration has an exact 1:1
mapping to and from JSON, improved error
messages, and support for comments. Read More
Template Syntax
The new template syntax supports loops and
conditionals directly in a Terraform configuration.
Read More

Copyright © 2017 HashiCorp 60
How it works
For Expressions
A for expression is available for iterating and
filtering lists and map values. This expression
always can be used anywhere a list or map is
expected. Read more
Generalize “Splat” Operator
The special resource.*.field syntax used to
only work for resources with count set. This is now a
generalized operator that works for any list value.
Read more
More Powerful Programmability
Conditional Improvements and Null Value
The conditional operator ... ? ... : ... now
supports any value type and lazily evaluates results,
as those familiar with this operator in other
languages would expect. Also, the special value null
can now be assigned to any field to represent the
absence of a value. Read More
Dynamic Blocks
Nested blocks such as rule in
aws_security_group or tags can be
dynamically generated based on lists/maps and
support iteration. Read more

Terraform 0.12 Deep Dive: HCL 2.0 for Infrastructure as Code, Remote Plan & Apply

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Terraform 0.12 Deep Dive: HCL 2.0 for Infrastructure as Code, Remote Plan & Apply