Immutable infrastructure concept in Terraform - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Immutable Infrastructure Benefits

Which of the following is the primary benefit of using immutable infrastructure?

A It reduces configuration drift by replacing servers instead of changing them.

B It allows quick updates by modifying existing servers directly.

C It requires manual intervention for every update to ensure accuracy.

D It increases downtime because servers are updated in place.

💡 Hint

Think about how replacing servers instead of changing them affects consistency.

Immutable infrastructure means servers are replaced rather than changed, which reduces errors and configuration drift.

❓ Architecture

intermediate

Immutable Infrastructure Deployment Pattern

In an immutable infrastructure deployment, what is the recommended approach to update an application running on cloud servers?

A Deploy a new server image with the updated application and replace old servers.

B SSH into each server and update the application manually.

C Patch the running servers with update scripts during maintenance windows.

D Use configuration management tools to change application files on live servers.

💡 Hint

Consider how immutable infrastructure treats servers as replaceable units.

Immutable infrastructure updates by deploying new server images and replacing old ones, avoiding manual or live changes.

❓ Configuration

advanced

Terraform Immutable Infrastructure Example

Given the following Terraform snippet, what will happen when you change the AMI ID and apply the configuration?

resource "aws_instance" "web" {
  ami           = "ami-12345678"
  instance_type = "t2.micro"
  tags = {
    Name = "web-server"
  }
}

Terraform

resource "aws_instance" "web" {
  ami           = "ami-12345678"
  instance_type = "t2.micro"
  tags = {
    Name = "web-server"
  }
}

A Terraform will update the existing instance in place with the new AMI.

B Terraform will destroy the old instance and create a new one with the new AMI.

C Terraform will ignore the AMI change and keep the old instance.

D Terraform will throw a syntax error due to missing lifecycle block.

💡 Hint

Think about how Terraform handles changes to immutable properties like AMI.

Changing the AMI causes Terraform to replace the instance because AMI is immutable for an existing instance.

❓ security

advanced

Security Advantages of Immutable Infrastructure

Which security advantage is most directly improved by adopting immutable infrastructure?

A Increased complexity in managing firewall rules.

B Easier manual auditing of server configurations.

C Ability to patch live servers quickly without downtime.

D Reduced risk of unauthorized changes persisting on servers.

💡 Hint

Consider how replacing servers affects unauthorized changes.

Immutable infrastructure reduces risk of unauthorized changes because servers are replaced rather than modified.

❓ service_behavior

expert

Behavior of Load Balancer During Immutable Deployment

During an immutable infrastructure deployment, how should a load balancer be configured to minimize downtime when replacing backend servers?

A Keep old and new servers in the load balancer simultaneously without health checks.

B Remove old servers immediately before creating new servers to avoid conflicts.

C Remove old servers from the load balancer only after new servers pass health checks.

D Manually switch traffic to new servers after all old servers are terminated.

💡 Hint

Think about how to keep service available during server replacement.

Removing old servers only after new ones are healthy ensures continuous service without downtime.