Dynamic blocks in ingress rules in Terraform - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a dynamic block in Terraform?

A dynamic block lets you generate multiple nested blocks inside a resource or module based on a list or map. It helps avoid repeating similar blocks manually.

beginner

Why use dynamic blocks in ingress rules?

Dynamic blocks allow you to create multiple ingress rules flexibly from a list of rules, making your Terraform code cleaner and easier to maintain.

intermediate

How do you reference the current item inside a dynamic block?

Inside a dynamic block, you use the special variable each.value to access the current item from the list or map you are looping over.

intermediate

Example syntax of a dynamic block for ingress rules?

Example:<br>

dynamic "ingress" {
  for_each = var.ingress_rules
  content {
    from_port   = each.value.from_port
    to_port     = each.value.to_port
    protocol    = each.value.protocol
    cidr_blocks = each.value.cidr_blocks
  }
}

beginner

What happens if the list used in a dynamic block is empty?

If the list is empty, Terraform generates no nested blocks for that dynamic block, so no ingress rules are created.

What does the for_each argument do in a dynamic block?

A Loops over a list or map to create multiple nested blocks

B Defines the resource type

C Specifies the provider version

D Sets the variable type

The for_each in a dynamic block loops over a collection to generate multiple nested blocks dynamically.

Which variable gives access to the current item inside a dynamic block?

A this

B each.value

C current

D item

Inside a dynamic block, each.value refers to the current element being processed.

What is the main benefit of using dynamic blocks in ingress rules?

A Avoids repeating similar ingress blocks manually

B Improves network speed

C Automatically updates Terraform version

D Encrypts ingress traffic

Dynamic blocks help avoid manual repetition by generating multiple ingress blocks from data.

If the list used in a dynamic block is empty, what happens?

A Terraform skips the resource

B Terraform throws an error

C Terraform creates one default block

D No nested blocks are created

An empty list means no nested blocks are generated inside the dynamic block.

Which Terraform resource commonly uses dynamic blocks for ingress rules?

A aws_s3_bucket

B aws_instance

C aws_security_group

D aws_lambda_function

The aws_security_group resource often uses dynamic blocks to define multiple ingress rules.

Explain how dynamic blocks simplify managing multiple ingress rules in Terraform.

Think about how you would write many similar blocks without repeating code.

Describe the syntax and key parts of a dynamic block used inside an aws_security_group resource for ingress rules.

Focus on how the dynamic block is structured and how it uses the input data.