Terraform Tutorial — Outputs Practice Exercises

Practice declaring and querying Terraform outputs.

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Exercise 1: Basic Output

Task: Write an output block that displays the ARN of an S3 bucket resource named aws_s3_bucket.logs.

Answer

output "logs_bucket_arn" {
  value       = aws_s3_bucket.logs.arn
  description = "ARN of the logs S3 bucket"
}

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Exercise 2: Sensitive Output

Task: You have a resource aws_db_instance.main with a password attribute that came from a sensitive variable. Write an output for the connection string.

Answer

output "db_connection_string" {
  value     = "postgresql://admin:${var.db_password}@${aws_db_instance.main.endpoint}/mydb"
  sensitive = true
}

The sensitive = true is required because the output references var.db_password, which is a sensitive variable.

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Exercise 3: Querying Outputs

Task: You need to get the bucket name from Terraform output and use it in a shell script to upload files. Write the bash commands.

Answer

# Get the bucket name without quotes
BUCKET=$(terraform output -raw bucket_name)

# Upload files
aws s3 sync ./build "s3://${BUCKET}"

The -raw flag strips the surrounding quotes from string outputs.

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Exercise 4: Module Outputs

Task: Your VPC module exposes vpc_id and subnet_ids. Write the root module code that calls the VPC module and creates an EC2 instance in the first subnet.

Answer

module "vpc" {
  source      = "./modules/vpc"
  cidr_block  = "10.0.0.0/16"
  environment = "dev"
}

resource "aws_instance" "web" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t3.micro"
  subnet_id     = module.vpc.subnet_ids[0]

  tags = {
    Name = "web-server"
  }
}

output "vpc_id" {
  value = module.vpc.vpc_id
}

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Chapter Summary

In this chapter, you learned:

• The output {} block with value, description, and sensitive
• terraform output to display values, -raw for scripts, -json for automation
• Sensitive outputs hide secrets from plan/apply but are accessible with -json and -raw
• Modules communicate through outputs — child exposes, parent consumes with module.<name>.<output>
• Practical output patterns for S3, EC2, RDS, VPC, and aggregate summaries

Next up: State — understanding how Terraform tracks your infrastructure.

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← Practical Output Examples State →