Question

A retail company runs a stateless product-catalog API on a managed instance group behind an external HTTP(S) load balancer in a single region (us-central1). Analytics show that during a nightly 3-hour reporting batch, backend CPU spikes to 95% while during business hours it hovers around 30%. The team wants to reduce compute spend without harming daytime response latency, and the reporting batch can tolerate slightly higher latency. Which change best optimizes cost while preserving daytime performance?

Accepted Answer

Configure a scheduled autoscaling policy on the MIG that raises the minimum instance count only during the nightly batch window, and keep a CPU-utilization target scaling policy for the rest of the day.

Answer

Purchase a 3-year committed use discount sized for the nightly peak CPU so the batch never throttles.

Answer

Set a fixed instance count equal to the nightly peak so the group never needs to scale during business hours.

Answer

Migrate the API to Spot VMs to lower per-instance cost across all hours of the day.