Dynamic block syntax 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, making configuration flexible and reusable.

beginner

Which keyword starts a dynamic block in Terraform?

The keyword dynamic starts a dynamic block, followed by the block type in quotes, like dynamic "ingress".

intermediate

What are the two main parts inside a dynamic block?

Inside a dynamic block, you have for_each to loop over a collection, and content which defines the block structure to repeat.

intermediate

Why use dynamic blocks instead of static blocks?

Dynamic blocks reduce repetition by generating multiple blocks from data, making configurations easier to maintain and adapt to changing inputs.

advanced

Show a simple example of a dynamic block creating multiple ingress rules.

Example:<br>

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
  }
}

What does the for_each attribute inside a dynamic block do?

A Loops over a collection to create multiple nested blocks

B Defines the type of resource to create

C Specifies the provider for the resource

D Sets the block's name

for_each loops over a list or map to generate multiple nested blocks dynamically.

Which part of a dynamic block defines the repeated block's structure?

A block_type

B for_each

C variable

D content

The content block defines the structure of each repeated nested block.

True or False: Dynamic blocks can only be used inside resource blocks.

A True

B False

C Only in modules

D Only in variables

Dynamic blocks can be used inside resources, modules, and other block types that support nested blocks.

What happens if the for_each collection is empty in a dynamic block?

A One empty block is created

B Terraform throws an error

C No nested blocks are created

D Terraform ignores the resource

If for_each is empty, no nested blocks are generated inside the dynamic block.

Which of these is a benefit of using dynamic blocks?

A Avoids repeating similar blocks manually

B Increases Terraform plan time significantly

C Requires writing more code

D Limits resource scalability

Dynamic blocks help avoid manual repetition by generating blocks from data collections.

Explain how a dynamic block works in Terraform and when you would use it.

Think about how to create multiple similar blocks from a list or map.

Describe the structure of a dynamic block with an example of creating multiple ingress rules.

Imagine you want to add many firewall rules without writing each one manually.