An internal application on Compute Engine has become slow recently. What is the first action to diagnose the root cause?

The first action to diagnose a slow application is to inspect logs and metrics. Cloud Logging provides application and system logs, which can reveal errors or unusual activity. Cloud Monitoring offers metrics like CPU utilization, memory usage, disk I/O, and network traffic, helping pinpoint resource bottlenecks. Changing the machine type is a potential solution, but it's premature without understanding the problem. Restoring a database backup is only relevant if data corruption is suspected and doesn't help diagnose performance issues. Deploying in a managed instance group with autoscaling and a load balancer is a scaling solution, not a diagnostic step, and may mask the underlying problem without identifying its cause.