Numeric functions (min, max, ceil) in Terraform - Mini Project: Build & Apply

Using Numeric Functions in Terraform

📖 Scenario: You are setting up a Terraform configuration to manage cloud resources. You need to use numeric functions to control resource counts and sizes based on given values.

🎯 Goal: Build a Terraform configuration that uses min, max, and ceil functions to calculate resource parameters.

📋 What You'll Learn

Create a variable with a list of numbers

Create a variable with a decimal number

Use min and max functions on the list

Use ceil function on the decimal number

💡 Why This Matters

🌍 Real World

Cloud engineers often need to calculate resource sizes or counts dynamically based on input values. Numeric functions like min, max, and ceil help automate these decisions.

💼 Career

Understanding Terraform numeric functions is essential for writing flexible infrastructure code that adapts to different environments and requirements.

1

Create a variable called numbers with the list [3, 7, 2, 9, 5]

Create a Terraform variable named numbers and assign it the list [3, 7, 2, 9, 5].

Terraform

variable "numbers" {
  # Your code here
}

Hint

Use variable "numbers" { default = [...] } syntax to define the list.

2

Create a variable called decimal_value with the value 4.3

Create a Terraform variable named decimal_value and assign it the decimal number 4.3.

Terraform

variable "numbers" {
  default = [3, 7, 2, 9, 5]
}

variable "decimal_value" {
  # Your code here
}

Hint

Use variable "decimal_value" { default = 4.3 } syntax to define the decimal number.

3

Create locals min_number and max_number using min and max functions on var.numbers

Create a locals block with two variables: min_number set to the minimum value of var.numbers using the min function, and max_number set to the maximum value of var.numbers using the max function.

Terraform

variable "numbers" {
  default = [3, 7, 2, 9, 5]
}

variable "decimal_value" {
  default = 4.3
}

locals {
  # Your code here
}

Hint

Use min(var.numbers) and max(var.numbers) inside locals.

4

Add a local ceil_value using the ceil function on var.decimal_value

In the existing locals block, add a variable called ceil_value that uses the ceil function on var.decimal_value.

Terraform

variable "numbers" {
  default = [3, 7, 2, 9, 5]
}

variable "decimal_value" {
  default = 4.3
}

locals {
  min_number = min(var.numbers)
  max_number = max(var.numbers)
  # Your code here
}

Hint

Add ceil_value = ceil(var.decimal_value) inside locals.

Practice

1. What does the Terraform function min(3, 7, 2) return?

easy

A. Error

B. 3

C. 7

D. 2

Solution

1. Step 1: Understand the min function

   The min function returns the smallest number from the given list.

2. Step 2: Compare the numbers 3, 7, and 2

   Among 3, 7, and 2, the smallest number is 2.

3. Final Answer:

   2 -> Option D

4. Quick Check:

   min(3,7,2) = 2 [OK]

Hint: min returns the smallest number from the list [OK]

Common Mistakes:

• Confusing min with max
• Expecting average instead of minimum
• Using ceil instead of min

2. Which of the following is the correct syntax to use the ceil function in Terraform?

easy

A. ceil(4.3)

B. ceil 4.3

C. ceil[4.3]

D. ceil{4.3}

Solution

1. Step 1: Recall Terraform function syntax

   Terraform functions use parentheses to enclose arguments, like function_name(argument).

2. Step 2: Check each option

   Only ceil(4.3) uses correct function call syntax.

3. Final Answer:

   ceil(4.3) -> Option A

4. Quick Check:

   Function calls use parentheses [OK]

Hint: Terraform functions always use parentheses for arguments [OK]

Common Mistakes:

• Using spaces instead of parentheses
• Using brackets or braces instead of parentheses
• Missing parentheses

3. What is the output of this Terraform expression?
max(5, ceil(3.2), min(4, 2))

medium

A. 2

B. 5

C. 3

D. 4

Solution

1. Step 1: Evaluate inner functions

   ceil(3.2) rounds 3.2 up to 4.
   min(4, 2) returns 2.

2. Step 2: Evaluate max function

   Now the expression is max(5, 4, 2). The largest number is 5.

3. Final Answer:

   5 -> Option B

4. Quick Check:

   max(5,4,2) = 5 [OK]

Hint: Evaluate inner functions first, then apply max [OK]

Common Mistakes:

• Ignoring nested function calls
• Mixing up min and max
• Forgetting ceil rounds up

4. Identify the error in this Terraform expression:
ceil(5.7, 2)

medium

A. Invalid function name

B. Missing parentheses

C. Too many arguments for ceil function

D. ceil cannot be used with decimals

Solution

1. Step 1: Check the ceil function signature

   The ceil function takes exactly one argument, a decimal number.

2. Step 2: Analyze the given expression

   The expression ceil(5.7, 2) has two arguments, which is invalid.

3. Final Answer:

   Too many arguments for ceil function -> Option C

4. Quick Check:

   ceil expects one argument [OK]

Hint: ceil takes only one decimal argument [OK]

Common Mistakes:

• Passing multiple arguments
• Confusing ceil with round
• Using wrong argument types

5. You want to find the smallest whole number greater than or equal to the minimum of 3.4, 2.1, and 5.9 in Terraform. Which expression achieves this?

hard

A. ceil(min(3.4, 2.1, 5.9))

B. min(ceil(3.4, 2.1, 5.9))

C. max(min(3.4, 2.1, 5.9))

D. ceil(max(3.4, 2.1, 5.9))

Solution

1. Step 1: Find the minimum of the numbers

   min(3.4, 2.1, 5.9) returns 2.1, the smallest number.

2. Step 2: Apply ceil to round up to the nearest whole number

   ceil(2.1) rounds 2.1 up to 3.

3. Final Answer:

   ceil(min(3.4, 2.1, 5.9)) -> Option A

4. Quick Check:

   min=2.1, ceil(2.1)=3 [OK]

Hint: Apply min first, then ceil to round up [OK]

Common Mistakes:

• Applying ceil before min
• Using max instead of min
• Confusing order of functions