Resource block syntax in Terraform - Mini Project: Build & Apply

Resource block syntax

📖 Scenario: You are setting up a simple cloud infrastructure using Terraform. You want to create a virtual machine instance on a cloud provider.

🎯 Goal: Build a Terraform configuration with a resource block that defines a virtual machine instance with specific properties.

📋 What You'll Learn

Create a resource block for an aws_instance named example

Set the ami attribute to "ami-0c55b159cbfafe1f0"

Set the instance_type attribute to "t2.micro"

Add a tags block with key Name and value ExampleInstance

💡 Why This Matters

🌍 Real World

Terraform resource blocks are the building blocks for defining cloud infrastructure in code. This skill helps automate cloud resource creation.

💼 Career

Cloud engineers and DevOps professionals use Terraform resource blocks daily to manage infrastructure efficiently and reliably.

1

Create the resource block skeleton

Write a Terraform resource block for an aws_instance named example with empty curly braces {}.

Terraform

# Write the resource block header for aws_instance named example
# Your code here

Hint

Start with resource "aws_instance" "example" { } to define the resource block.

2

Add AMI and instance type

Inside the resource "aws_instance" "example" block, add the attribute ami set to "ami-0c55b159cbfafe1f0" and the attribute instance_type set to "t2.micro".

Terraform

resource "aws_instance" "example" {
  # Add ami and instance_type attributes here
  # Your code here
}

Hint

Use ami = "ami-0c55b159cbfafe1f0" and instance_type = "t2.micro" inside the resource block.

3

Add tags block

Inside the resource "aws_instance" "example" block, add a tags block with a key Name and value ExampleInstance.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
  # Add tags block here
  # Your code here
}

Hint

Use a tags block with Name = "ExampleInstance" inside the resource block.

4

Complete the resource block

Ensure the resource "aws_instance" "example" block is properly closed with a closing curly brace } and all attributes are correctly indented.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"

  tags = {
    Name = "ExampleInstance"
  }
  # Close the resource block here
  # Your code here
}

Hint

Make sure the resource block ends with a closing curly brace }.

Practice

1. What is the correct way to start a resource block in Terraform?

easy

A. resource "aws_instance" { example }

B. resource aws_instance example { }

C. resource "example" "aws_instance" { }

D. resource "aws_instance" "example" { }

Solution

1. Step 1: Understand resource block syntax

   A resource block starts with the keyword resource, followed by the resource type in quotes, then the resource name in quotes.

2. Step 2: Match the correct syntax

   resource "aws_instance" "example" { } correctly uses resource "aws_instance" "example" { }, which matches the required syntax.

3. Final Answer:

   resource "aws_instance" "example" { } -> Option D

4. Quick Check:

   Resource block syntax = resource "type" "name" { } [OK]

Hint: Resource block always uses resource "type" "name" [OK]

Common Mistakes:

• Omitting quotes around type or name
• Swapping type and name order
• Using braces incorrectly

2. Which of the following is a valid property assignment inside a Terraform resource block?

easy

A. instance_type = t2.micro

B. instance_type => "t2.micro"

C. instance_type = "t2.micro"

D. instance_type: "t2.micro"

Solution

1. Step 1: Identify correct property syntax

   Terraform uses = to assign values, and string values must be in quotes.

2. Step 2: Check each option

   instance_type = "t2.micro" uses instance_type = "t2.micro", which is correct. instance_type = t2.micro misses quotes, B and C use invalid assignment symbols.

3. Final Answer:

   instance_type = "t2.micro" -> Option C

4. Quick Check:

   Property assignment uses = and quotes for strings [OK]

Hint: Use = and quotes for string values inside resource blocks [OK]

Common Mistakes:

• Forgetting quotes around string values
• Using colon or arrow instead of =
• Missing equal sign

3. Given this resource block snippet, what will Terraform create?

resource "aws_s3_bucket" "mybucket" {
  bucket = "my-unique-bucket-123"
  acl    = "private"
}

medium

A. An S3 bucket named "mybucket" with public access

B. An S3 bucket named "my-unique-bucket-123" with private access

C. An S3 bucket named "aws_s3_bucket" with private access

D. A storage container with default public access

Solution

1. Step 1: Identify resource type and name

   The resource type is aws_s3_bucket, and the resource name is mybucket. The bucket property sets the actual bucket name.

2. Step 2: Understand properties

   The bucket property sets the bucket's real name to "my-unique-bucket-123". The acl is set to "private", meaning no public access.

3. Final Answer:

   An S3 bucket named "my-unique-bucket-123" with private access -> Option B

4. Quick Check:

   Bucket name = property value, ACL = private [OK]

Hint: Bucket name is from bucket property, not resource name [OK]

Common Mistakes:

• Confusing resource name with actual bucket name
• Assuming default ACL is public
• Ignoring property values inside the block

4. Identify the error in this Terraform resource block:

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

medium

A. Missing quotes around the instance_type value

B. Resource block missing closing brace

C. Incorrect resource type name

D. Missing resource name

Solution

1. Step 1: Check property value syntax

   The instance_type property value t2.micro is missing quotes, which is required for string values.

2. Step 2: Verify block structure

   The resource block has correct braces and resource type/name, so no errors there.

3. Final Answer:

   Missing quotes around the instance_type value -> Option A

4. Quick Check:

   String values must be quoted [OK]

Hint: Always quote string values inside resource blocks [OK]

Common Mistakes:

• Forgetting quotes around string properties
• Assuming braces are optional
• Mixing resource type and name order

5. You want to create two AWS EC2 instances with different names but the same AMI and instance type using resource blocks. Which is the best way to write this in Terraform?

hard

A. resource "aws_instance" "web1" {
ami = "ami-abc123"
instance_type = "t2.micro"
}
resource "aws_instance" "web2" {
ami = "ami-abc123"
instance_type = "t2.micro"
}

B. resource "aws_instance" "web" {
count = 2
ami = "ami-abc123"
instance_type = "t2.micro"
}

C. resource "aws_instance" "web" {
ami = "ami-abc123"
instance_type = "t2.micro"
name = ["web1", "web2"]
}

D. resource "aws_instance" "web" {
ami = "ami-abc123"
instance_type = "t2.micro"
for_each = ["web1", "web2"]
}

Solution

1. Step 1: Understand resource naming and duplication

   Each resource block must have a unique name.

   resource "aws_instance" "web1" {
     ami = "ami-abc123"
     instance_type = "t2.micro"
   }
   resource "aws_instance" "web2" {
     ami = "ami-abc123"
     instance_type = "t2.micro"
   }

   defines two separate resources with different names.

2. Step 2: Evaluate other options

   resource "aws_instance" "web" {
     count = 2
     ami = "ami-abc123"
     instance_type = "t2.micro"
   }

   uses count but does not differentiate names.

   resource "aws_instance" "web" {
     ami = "ami-abc123"
     instance_type = "t2.micro"
     name = ["web1", "web2"]
   }

   tries to assign a list to name property, which is invalid.

   resource "aws_instance" "web" {
     ami = "ami-abc123"
     instance_type = "t2.micro"
     for_each = ["web1", "web2"]
   }

   uses for_each incorrectly without mapping names.

3. Final Answer:

   Define two separate resource blocks with unique names -> Option A

4. Quick Check:

   Unique resource names needed for multiple instances [OK]

Hint: Use separate resource blocks with unique names for multiple instances [OK]

Common Mistakes:

• Using count without unique names
• Assigning list to single property
• Misusing for_each without proper keys