Code review for infrastructure changes in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a resource block for an AWS S3 bucket.

Terraform

resource "aws_s3_bucket" "my_bucket" {
  bucket = [1]
  acl    = "private"
}

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

Abucket_name

Bmy_bucket

C"public-read"

D"my-unique-bucket-name"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name without quotes

Using an ACL value instead of bucket name

Omitting quotes around the bucket name

The bucket name must be a string literal with quotes, representing the unique bucket name.

2fill in blank

medium

Complete the code to specify the AWS region in the provider block.

Terraform

provider "aws" {
  region = [1]
}

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

Aregion

B"us-west-2"

Cus-west-2

Daws_region

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting quotes around the region name

Using variable names without defining them

The region value must be a string literal enclosed in quotes.

3fill in blank

hard

Fix the error in the resource block by completing the lifecycle rule to prevent bucket deletion.

Terraform

resource "aws_s3_bucket" "my_bucket" {
  bucket = "my-unique-bucket-name"

  lifecycle {
    [1] = true
  }
}

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

Ablock_deletion

Bprevent_delete

Cprevent_destroy

Ddisable_destroy

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect lifecycle attribute names

Confusing lifecycle rules with resource attributes

The correct lifecycle argument to prevent resource destruction is 'prevent_destroy'.

4fill in blank

hard

Fill both blanks to create an output that shows the bucket ARN.

Terraform

output "bucket_arn" {
  value = aws_s3_bucket.my_bucket[1][2]
}

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

A.

B[

Carn

D]

Attempts:

3 left

💡 Hint

Common Mistakes

Using brackets instead of dot notation

Using incorrect attribute names

To access the ARN attribute, use dot notation: aws_s3_bucket.my_bucket.arn

5fill in blank

hard

Fill all three blanks to define a variable with a default value and description.

Terraform

variable "bucket_name" {
  type        = [1]
  default     = [2]
  description = [3]
}

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

A"string"

B"my-default-bucket"

C"The name of the S3 bucket"

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Quoting the type value

Omitting quotes around default or description

Using incorrect variable syntax

The type is unquoted 'string', default and description are string literals with quotes.

Practice

1. What is the main purpose of running terraform plan before applying changes?

easy

A. To apply the changes directly to the cloud resources

B. To preview the changes Terraform will make to the infrastructure

C. To delete all existing infrastructure

D. To create a backup of the current infrastructure state

Solution

1. Step 1: Understand the role of terraform plan

   This command shows what changes Terraform will perform without making any actual changes.

2. Step 2: Differentiate from other commands

   terraform apply makes changes, while terraform plan previews them safely.

3. Final Answer:

   To preview the changes Terraform will make to the infrastructure -> Option B

4. Quick Check:

   Preview changes = terraform plan [OK]

Hint: Remember: plan previews, apply executes changes [OK]

Common Mistakes:

• Confusing plan with apply
• Thinking plan deletes resources
• Assuming plan creates backups

2. Which of the following is the correct syntax to initialize a Terraform working directory?

easy

A. terraform init

B. terraform start

C. terraform setup

D. terraform configure

Solution

1. Step 1: Identify the initialization command

   terraform init sets up the working directory by downloading providers and preparing backend.

2. Step 2: Verify other options

   Commands like terraform start, terraform setup, and terraform configure do not exist in Terraform CLI.

3. Final Answer:

   terraform init -> Option A

4. Quick Check:

   Initialize = terraform init [OK]

Hint: Init means start setup in Terraform [OK]

Common Mistakes:

• Using non-existent commands
• Confusing init with apply
• Assuming configure is a Terraform command

3. Given this Terraform snippet:

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

output "instance_id" {
  value = aws_instance.example.id
}

What will terraform apply output after successful deployment?

medium

A. The ID of the created AWS instance

B. The AMI ID used in the instance

C. The instance type string

D. An error because output is missing

Solution

1. Step 1: Understand the output block

   The output named instance_id returns the ID of the created AWS instance resource.

2. Step 2: Confirm output value

   The value is set to aws_instance.example.id, which is the unique instance ID assigned by AWS.

3. Final Answer:

   The ID of the created AWS instance -> Option A

4. Quick Check:

   Output shows instance ID = The ID of the created AWS instance [OK]

Hint: Output shows resource attributes, not input values [OK]

Common Mistakes:

• Confusing output value with input AMI
• Expecting instance type as output
• Thinking output block is missing or invalid

4. You see this Terraform code snippet in a pull request:

resource "aws_s3_bucket" "my_bucket" {
  bucket = "my-unique-bucket-name"
  acl    = "public-read"
}

What is the main concern during code review before applying?

medium

A. The bucket name might not be unique globally

B. The code is missing a region specification

C. The resource type is incorrect for S3 buckets

D. The ACL setting makes the bucket publicly readable, which may be a security risk

Solution

1. Step 1: Analyze the ACL setting

   The ACL is set to public-read, which allows anyone on the internet to read bucket contents.

2. Step 2: Consider security best practices

   Making buckets public can expose sensitive data; this should be reviewed carefully before applying.

3. Final Answer:

   The ACL setting makes the bucket publicly readable, which may be a security risk -> Option D

4. Quick Check:

   Public ACL = security risk [OK]

Hint: Watch for public access settings in code reviews [OK]

Common Mistakes:

• Ignoring security implications of ACL
• Assuming bucket name uniqueness is the main issue
• Thinking region is mandatory in resource block

5. A team wants to share Terraform infrastructure changes for review before applying. Which practice best supports safe collaboration?

hard

A. Send raw Terraform files via email for manual review

B. Run terraform apply directly on the main branch without review

C. Share terraform plan output in a pull request for team feedback

D. Apply changes first, then notify the team

Solution

1. Step 1: Understand collaboration best practices

   Sharing terraform plan output in pull requests allows the team to see proposed changes safely before applying.

2. Step 2: Evaluate other options

   Applying changes without review or sending raw files lacks safety and clarity; notifying after applying is risky.

3. Final Answer:

   Share terraform plan output in a pull request for team feedback -> Option C

4. Quick Check:

   Plan + PR = safe collaboration [OK]

Hint: Use plan output in PRs for safe team review [OK]

Common Mistakes:

• Skipping review before apply
• Sharing raw files without context
• Applying changes before team agreement