Meta-arguments overview in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to use the meta-argument that controls resource creation count.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-123456"
  instance_type = "t2.micro"
  [1] = 3
}

Drag options to blanks, or click blank then click option'

Afor_each

Bdepends_on

Ccount

Dlifecycle

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'depends_on' instead of 'count' to create multiple resources.

Confusing 'for_each' with 'count' for simple multiple resource creation.

The count meta-argument tells Terraform how many instances of the resource to create.

2fill in blank

medium

Complete the code to use the meta-argument that defines dependencies between resources.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-123456"
  instance_type = "t2.micro"
  [1] = [aws_security_group.sg]
}

Drag options to blanks, or click blank then click option'

Adepends_on

Bcount

Cfor_each

Dprovider

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'count' to manage dependencies instead of 'depends_on'.

Not specifying dependencies causing resource creation errors.

The depends_on meta-argument explicitly defines resource dependencies to control creation order.

3fill in blank

hard

Fix the error in the code by choosing the correct meta-argument to iterate over a map.

Terraform

resource "aws_s3_bucket" "example" {
  [1] = var.bucket_names
  bucket = [1].value
}

Drag options to blanks, or click blank then click option'

Acount

Bfor_each

Cdepends_on

Dprovider

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'count' with maps instead of 'for_each'.

Trying to access '.value' without using 'for_each'.

The for_each meta-argument is used to create multiple resources from a map or set of strings.

4fill in blank

hard

Fill both blanks to correctly prevent Terraform from deleting a resource on destroy and to ignore changes to tags.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-123456"
  instance_type = "t2.micro"
  lifecycle {
    [1] = true
    [2] = ["tags"]
  }
}

Drag options to blanks, or click blank then click option'

Aprevent_destroy

Bignore_changes

Ccreate_before_destroy

Dreplace_triggered_by

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing 'create_before_destroy' with 'prevent_destroy'.

Not using 'ignore_changes' causing unwanted updates.

prevent_destroy stops Terraform from deleting the resource. ignore_changes tells Terraform to ignore changes to specified attributes like tags.

5fill in blank

hard

Fill all three blanks to correctly use meta-arguments to create multiple resources from a map, specify a provider, and define dependencies.

Terraform

resource "aws_instance" "example" {
  [1] = var.instances
  provider    = aws.[2]
  [3] = [aws_security_group.sg]
  ami           = "ami-123456"
  instance_type = "t2.micro"
}

Drag options to blanks, or click blank then click option'

Afor_each

Bus-east-1

Cdepends_on

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'count' instead of 'for_each' for maps.

Incorrect provider region name.

Omitting 'depends_on' causing resource creation order issues.

for_each creates resources from a map. provider specifies the AWS region. depends_on sets resource dependencies.

Practice

1. Which meta-argument in Terraform allows you to create multiple instances of a resource easily using an integer?

easy

A. count

B. depends_on

C. lifecycle

D. for_each

Solution

1. Step 1: Understand the purpose of count

   The count meta-argument lets you specify how many copies of a resource to create.

2. Step 2: Compare with other meta-arguments

   depends_on manages dependencies, lifecycle controls resource behavior, and for_each creates multiple instances but with keys, not just count.

3. Final Answer:

   count -> Option A

4. Quick Check:

   Multiple instances = count [OK]

Hint: Use count to repeat resources by number [OK]

Common Mistakes:

• Confusing count with depends_on
• Thinking lifecycle creates multiple resources
• Mixing count and for_each without understanding difference

2. Which of the following is the correct syntax to use the depends_on meta-argument in a resource block?

easy

A. depends_on = ["aws_instance.example"]

B. depends_on = aws_instance.example

C. depends_on = [aws_instance.example]

D. depends_on = [aws_instance.example.id]

Solution

1. Step 1: Recall depends_on syntax

   depends_on expects a list of resource references without quotes.

2. Step 2: Analyze options

   depends_on = [aws_instance.example] uses a list with resource reference correctly. depends_on = aws_instance.example misses list brackets. depends_on = ["aws_instance.example"] uses quotes making it a string, not a reference. depends_on = [aws_instance.example.id] uses an attribute which is invalid here.

3. Final Answer:

   depends_on = [aws_instance.example] -> Option C

4. Quick Check:

   List of resource references = depends_on = [aws_instance.example] [OK]

Hint: Always use square brackets with resource references for depends_on [OK]

Common Mistakes:

• Omitting brackets for depends_on list
• Using quotes around resource names
• Referencing resource attributes instead of resource itself

3. Given the following Terraform snippet:

resource "aws_instance" "example" {
  count = 3
  ami           = "ami-123456"
  instance_type = "t2.micro"
}

What will be the number of instances created and their resource addresses?

medium

A. 1 instance: aws_instance.example

B. 3 instances: aws_instance.example[0], aws_instance.example[1], aws_instance.example[2]

C. 3 instances: aws_instance.example.0, aws_instance.example.1, aws_instance.example.2

D. Error due to missing for_each

Solution

1. Step 1: Understand count behavior

   count = 3 creates three instances indexed from 0 to 2.

2. Step 2: Identify resource addresses format

   Terraform uses square brackets for indexed resources, so addresses are aws_instance.example[0], aws_instance.example[1], and aws_instance.example[2].

3. Final Answer:

   3 instances: aws_instance.example[0], aws_instance.example[1], aws_instance.example[2] -> Option B

4. Quick Check:

   Count creates indexed instances [OK]

Hint: Count creates indexed resources with square brackets [OK]

Common Mistakes:

• Thinking only one instance is created
• Using dot notation instead of brackets for indexes
• Confusing count with for_each syntax

4. You wrote this Terraform resource:

resource "aws_s3_bucket" "example" {
  for_each = ["a", "b"]
  bucket = each.value
}

What is the error in this configuration?

medium

A. Missing count argument

B. each.value is invalid inside resource blocks

C. bucket attribute cannot use each.value

D. for_each must be a map or set, not a list

Solution

1. Step 1: Check for_each type requirements

   for_each requires a map or set of strings, not a list.

2. Step 2: Analyze provided value

   The value is a list ["a", "b"], which is invalid for for_each. It should be a set or map.

3. Final Answer:

   for_each must be a map or set, not a list -> Option D

4. Quick Check:

   for_each needs map/set, not list [OK]

Hint: Use map or set for for_each, not list [OK]

Common Mistakes:

• Using list instead of set/map for for_each
• Misunderstanding each.value usage
• Confusing count and for_each requirements

5. You want to create multiple AWS EC2 instances with different names and ensure one instance is always created before the others. Which meta-arguments combination should you use?

hard

A. Use for_each with a map of names and depends_on to order creation

B. Use count with a number and lifecycle to order creation

C. Use depends_on only, no count or for_each

D. Use lifecycle with create_before_destroy only

Solution

1. Step 1: Choose meta-argument for multiple named instances

   for_each with a map lets you create instances with specific names as keys.

2. Step 2: Ensure creation order

   depends_on lets you specify that one resource must be created before others.

3. Final Answer:

   Use for_each with a map of names and depends_on to order creation -> Option A

4. Quick Check:

   Multiple named + order = for_each + depends_on [OK]

Hint: Combine for_each and depends_on for named ordered resources [OK]

Common Mistakes:

• Using count without names for multiple instances
• Relying on lifecycle for creation order
• Ignoring depends_on for resource dependencies