Instance templates in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Purpose of Instance Templates in GCP

What is the primary purpose of using an instance template in Google Cloud Platform?

A To store data persistently across VM instance restarts.

B To monitor the health of VM instances automatically.

C To define a reusable configuration for VM instances that can be used to create managed instance groups.

D To provide a graphical interface for managing VM instances.

💡 Hint

Think about how you can create multiple VMs with the same settings easily.

Instance templates let you save a VM configuration so you can create many VMs with the same setup, especially in managed instance groups.

❓ Configuration

intermediate

Instance Template Configuration Output

Given the following instance template configuration snippet, what will be the machine type of the VM instances created from it?

GCP

resource "google_compute_instance_template" "example" {
  name         = "example-template"
  machine_type = "e2-medium"
  disk {
    source_image = "debian-cloud/debian-11"
    auto_delete  = true
    boot         = true
  }
  network_interface {
    network = "default"
  }
}

A e2-medium

B n1-standard-1

C custom-2-4096

D f1-micro

💡 Hint

Look at the machine_type field in the configuration.

The machine_type field specifies the VM size. Here it is set to 'e2-medium'.

❓ Architecture

advanced

Scaling with Instance Templates and Managed Instance Groups

You want to automatically scale your web application based on CPU usage. Which architecture best uses instance templates to achieve this?

A Deploy a serverless function instead of using instance templates for scaling.

B Create a managed instance group using an instance template and configure autoscaling based on CPU utilization.

C Use instance templates only to create a single VM instance and scale by adding more templates.

D Manually create individual VM instances from the instance template and monitor CPU usage yourself.

💡 Hint

Think about how to automate scaling with instance templates.

Managed instance groups use instance templates to create identical VMs and can autoscale based on metrics like CPU usage.

❓ security

advanced

Security Best Practice with Instance Templates

Which practice improves security when using instance templates for VM creation?

A Include a startup script that installs the latest security patches automatically on boot.

B Store sensitive credentials directly in the instance template metadata.

C Use the default service account with full project permissions for all instances.

D Disable firewall rules to allow all incoming traffic for easier access.

💡 Hint

Consider how to keep instances secure and updated automatically.

Including a startup script to patch VMs on boot helps keep them secure. Storing credentials in metadata or using overly permissive accounts is unsafe.

❓ service_behavior

expert

Effect of Changing an Instance Template on Existing Managed Instances

You update an instance template used by a managed instance group. What happens to the existing VM instances in the group?

A The managed instance group deletes all instances and creates new ones instantly.

B All existing instances automatically update immediately to the new template configuration.

C The instance template update fails if instances already exist in the group.

D Existing instances remain unchanged until you manually trigger a rolling update or recreate them.

💡 Hint

Think about how managed instance groups handle updates to templates.

Updating an instance template does not change existing instances automatically. You must perform a rolling update or recreate instances to apply changes.