Terraform Associate Exam - Question 156

Question

You need to write some Terraform code that adds 42 firewall rules to a security group as shown in the example. What can you use to avoid writing 42 different nested ingress config blocks by hand?

Examice · Accepted Answer

A dynamic block in Terraform is used to generate multiple nested blocks based on the information provided in a loop, which is ideal for creating several similar sub-blocks without repeating code. This is particularly useful for avoiding the manual creation of multiple nested blocks, such as writing 42 different ingress blocks for a security group. By iterating over a collection of input values, a dynamic block can programmatically generate each nested ingress block, making the code more maintainable and concise.

Hizumi · Answer

Answer is D.
A dynamic block acts much like a for expression, but produces nested blocks instead of a complex typed value. It iterates over a given complex value, and generates a nested block for each element of that complex value.
Reference: https://www.terraform.io/language/expressions/dynamic-blocks

Bere · Answer

resource "aws_security_group" "many_rules" {
  name        = "many_rules"
  
  dynamic "ingress" {
    for_each = var.ingress_rules
    content {
      from_port   = ingress.value.from_port
      to_port     = ingress.value.to_port
      protocol    = ingress.value.protocol
      cidr_blocks = ingress.value.cidr_blocks
    }
  }
}

variable "ingress_rules" {
  description = "A list of ingress rules"
  type        = list(object({
    from_port   = number
    to_port     = number
    protocol    = string
    cidr_blocks = list(string)
  }))
  default = [
    {
      from_port   = 80
      to_port     = 80
      protocol    = "tcp"
      cidr_blocks = ["0.0.0.0/0"]
    },
    # Add 41 more rules here...
  ]
}

depal_dhir · Answer

https://www.terraform.io/language/expressions/dynamic-blocks

Rugaroo · Answer

Some additional information comparing each of the options: https://awstip.com/terraform-for-vs-for-each-7ff8506a1f94

Answer is definitely D as the question specifically mentions 'nested config(uration) blocks'

noodles16668 · Answer

https://developer.hashicorp.com/terraform/tutorials/configuration-language/count

InformationOverload · Answer

yep, D is correct.

Terraform Associate Exam - Question 156

Discussion