Answer: Autohealing with health checks

## Explanation To automatically recreate unhealthy VMs in a Managed Instance Group (MIG), you must configure **autohealing with health checks**. Here's why: **Autohealing with Health Checks:** - Autohealing is a feature of MIGs that automatically recreates instances that fail health checks - You define health checks (HTTP, HTTPS, TCP, or SSL) that monitor the health of your instances - When an instance fails the health check for a specified period, the MIG automatically recreates it - This ensures your application remains available and healthy **Why other options are incorrect:** **A) Firewall rules:** - Firewall rules control network traffic but don't automatically recreate unhealthy instances - They can affect connectivity but not instance health management **C) Preemptible instances:** - Preemptible instances are low-cost, short-lived VMs that can be terminated by Google Cloud - This is about cost optimization, not health monitoring and auto-recovery **D) Cloud Monitoring alerts:** - While Cloud Monitoring can alert you about unhealthy instances, it doesn't automatically recreate them - You would need to set up additional automation (like Cloud Functions) to respond to alerts **Key Takeaway:** Autohealing with health checks is the built-in MIG feature specifically designed to automatically replace unhealthy instances, making it the correct solution for this requirement.

Author: Rodrigo Sales