Explanation
GCP VM instances are provisioned with excess CPU or memory relative to actual needs, particularly with custom machine types or legacy templates. Instances consuming minimal resources compared to their allocation represent cost reduction opportunities through rightsizing. These oversized instances often go unnoticed, continuing to generate unnecessary charges.
Relevant Billing Model
Compute Engine VM instances are billed based on:
- Machine type and configuration — cost scales with vCPUs, memory, and premium features (GPUs, local SSDs)
- Uptime — charged per second with one-minute minimum
- Persistent disk and network usage
Detection
- Analyze average CPU and memory utilization of running Compute Engine instances
- Determine if actual usage justifies current machine type or custom configuration
- Review whether workloads could use smaller predefined or custom machine types
- Check for constraints such as licensing, startup latency, or performance overhead
- Validate with application or infrastructure teams regarding resize impact
Remediation
- Resize instances to smaller predefined or custom machine types aligned with observed usage
- For elastic workloads, consider managed instance groups with autoscaling
- Periodically review usage patterns for continued alignment with resource needs