Demo Count and for each

In this lab, you’ll learn how to leverage the count and for_each meta-arguments to create multiple resource instances dynamically in OpenTofu. We’ll work through a series of tasks:

Inspecting a basic configuration
Scaling with count
Parameterizing with variables
Ensuring uniqueness with for_each

Task 1: Inspect the Base Configuration

Navigate to your project directory:

cd /root/opentofu-projects/project-shade

Open the default main.tf:

resource "local_sensitive_file" "name" {
  filename = "/root/user-data"
  content  = "password: S3cr3tP@ssw0rd"
}

Since there’s only one resource block, running opentofu plan would create one file at /root/user-data.

Task 2: Create Multiple Instances with `count`

Add the count argument to generate three instances:

resource "local_sensitive_file" "name" {
  filename = "/root/user-data"
  content  = "password: S3cr3tP@ssw0rd"
  count    = 3
}

Initialize and preview:

opentofu init
opentofu plan

Expected plan excerpt:

# local_sensitive_file.name will be created with 3 instances
+ resource "local_sensitive_file" "name" {
    + count    = 3
    + filename = "/root/user-data"
    + content  = (sensitive)
  }

Apply the changes:

opentofu apply

All three instances target the same filepath, so you end up with just one actual file on disk.

Although Terraform plans three resources, they all write to /root/user-data. Use unique filenames or a loop index to avoid overwriting.

Task 3: Accessing Resources by Index

Resources managed with count form a list. To view the ID of the second element (index 1):

opentofu state show local_sensitive_file.name[1]

Look for the id attribute in the output.

Task 4: Parameterize with Variables and `count`

Define variables in variables.tf:

variable "users" {
  type = list(string)
}

variable "content" {
  default = "password: S3Cr3tP@ssw0rd"
}

Update main.tf:

resource "local_sensitive_file" "name" {
  count    = length(var.users)
  filename = var.users[count.index]
  content  = var.content
}

Now each users element becomes a filename. Initialize and apply:

opentofu init
opentofu plan
opentofu apply

Task 5: Set Default Values for Variables

Add sensible defaults in variables.tf:

variable "users" {
  type    = list(string)
  default = ["/root/user1", "/root/user11", "/root/user12"]
}

variable "content" {
  default = "password: S3Cr3tP@ssw0rd"
}

Key points:

Type of users: list(string)
List vs. set: Lists allow duplicates; sets do not.

Example of a duplicate in a list (invalid for a set):

variable "users" {
  default = [
    "/root/user10",
    "/root/user1",
    "/root/user12",
    "/root/user10"  # duplicate
  ]
}

Task 6: Ensure Unique Instances with `for_each`

Refactor main.tf to use for_each on a set:

resource "local_sensitive_file" "name" {
  for_each = toset(var.users)
  filename = each.value
  content  = var.content
}

The toset() function removes duplicates, and for_each creates a map keyed by each unique filename. Initialize and apply:

opentofu init
opentofu plan
opentofu apply

Expected output:

local_sensitive_file.name["/root/user10"]: Creating...
local_sensitive_file.name["/root/user11"]: Creating...
local_sensitive_file.name["/root/user12"]: Creating...
Apply complete! Resources: 3 added, 0 changed, 0 destroyed.

Eliminates duplicates automatically
Creates a map, so you can reference resources by key:
local_sensitive_file.name["/root/user11"]

Comparing `count` vs. `for_each`

Feature	count	for_each
Data structure	List (indexed)	Map (keyed by value)
Handling duplicates	Requires manual deduplication	Automatic when using `toset()`
Reference syntax	`resource.name[0]`	`resource.name["key"]`

Q&A

What data structure does for_each produce?
A map, keyed by each unique element.
How do you address the resource for /root/user11 with for_each?
local_sensitive_file.name["/root/user11"]

Watch Video

Practice Lab

Meta Arguments amp Count and for each

Version Constraints

Course Introduction

Introduction to Infrastructure as Code

OpenTofu Basics

OpenTofu State

Working with OpenTofu

Remote State

OpenTofu Provisioners

OpenTofu Import, Tainting Resources and Deubugging

OpenTofu Modules

OpenTofu Functions and Conditional Expressions

OpenTofu: Beyond Basics

Course Conclusion

Getting Started with OpenTofu

Demo Count and for each

Task 1: Inspect the Base Configuration

Task 2: Create Multiple Instances with `count`

Task 3: Accessing Resources by Index

Task 4: Parameterize with Variables and `count`

Task 5: Set Default Values for Variables

Task 6: Ensure Unique Instances with `for_each`

Comparing `count` vs. `for_each`

Q&A

Further Reading

Watch Video

Practice Lab

​Task 1: Inspect the Base Configuration

​Task 2: Create Multiple Instances with count

​Task 3: Accessing Resources by Index

​Task 4: Parameterize with Variables and count

​Task 5: Set Default Values for Variables

​Task 6: Ensure Unique Instances with for_each

​Comparing count vs. for_each

​Q&A

​Further Reading

Watch Video

Practice Lab

Task 1: Inspect the Base Configuration

Task 2: Create Multiple Instances with `count`

Task 3: Accessing Resources by Index

Task 4: Parameterize with Variables and `count`

Task 5: Set Default Values for Variables

Task 6: Ensure Unique Instances with `for_each`

Comparing `count` vs. `for_each`

Q&A

Further Reading