GCP Idle Resources

GCP Idle Resources Skill

Detect unused and idle GCP resources with anti-hallucination guardrails and cost waste estimation.

Relationship to other GCP skills:

• gcp-idle-resources/ -> "What is wasting money" (idle detection rules, cost estimation, protection label checks)
• gcp/ -> "How to execute" (parallel patterns, filtering, monitoring aligners, billing/pricing scripts)
• gcp-rightsizing/ -> "What is oversized" (utilization thresholds, downsize recommendations)

CRITICAL: Idle Resource Detection Rules (Anti-Hallucination)

These rules are MANDATORY when detecting idle resources. Violating them produces recommendations that can cause data loss or outages.

Rule 1: Unattached Persistent Disk != Always Deletable

Detached PDs (no users field) may be intentional (warm standby, manual backups, data archives). Report but NEVER auto-recommend deletion without user context.

WRONG:  "disk-abc is detached, delete it"
CORRECT: "disk-abc is detached, candidate for review. Created 2025-06-15, 100GiB pd-ssd, est. $17/mo"

Rule 2: Stopped VMs (TERMINATED) Still Incur PD + IP Costs

When a Compute Engine instance is stopped (status=TERMINATED), compute charges stop but attached Persistent Disks and reserved External IPs continue to incur charges.

MANDATORY: Report the ongoing cost of stopped instances, not just the compute savings.

WRONG:  "vm-abc is stopped, no cost"
CORRECT: "vm-abc is stopped since 2025-12-01. Ongoing cost: 2x PDs ($24/mo) + 1 external IP ($7.20/mo) = $31.20/mo"

Rule 3: External IP Cost: $0.010/hr ($7.20/mo) When Unused

Since February 2024, GCP charges for ALL external IPv4 addresses. Unused reserved IPs (status=RESERVED, not attached to any resource) cost $0.010/hr ($7.20/mo). In-use IPs on standard VMs cost $0.004/hr ($2.88/mo). IPs on forwarding rules are free.

WRONG:  "External IP attached to running instance is free"
CORRECT: "All external IPs cost money. IP 35.x.x.x is RESERVED (unattached) -- $7.20/mo pure waste"

Rule 4: Cloud NAT: $0.0014/hr Per VM (Capped at $0.044/hr) + $0.045/GB

Cloud NAT charges per VM instance using the gateway ($0.0014/hr per VM, capped at $0.044/hr for 32+ VMs), plus $0.045/GB data processed. Even idle Cloud NAT gateways with a few VMs incur cost.

WRONG:  "Cloud NAT has low traffic, minimal cost"
CORRECT: "Cloud NAT nat-abc serves 5 VMs but < 10 active connections/day avg. Fixed cost: ~$5.04/mo + data processing"

Rule 5: Snapshot Cost: $0.050/GiB/mo (Standard Regional)

Old snapshots accumulate silently. 1TiB of old snapshots = $51.20/mo. Snapshots backing machine images are required.

MANDATORY: Cross-reference with gcloud compute images list and gcloud compute machine-images list to exclude snapshots backing active images before flagging.

WRONG:  "snap-abc is 90 days old, delete it"
CORRECT: "snap-abc is 90 days old, 200GiB, est. $10/mo. NOT backing any image. Candidate for review."
CORRECT: "snap-def is 120 days old, 500GiB. BACKS image image-xyz -- skipped (required by image)."

Rule 6: Never Recommend Deletion -- Only Flag

Always phrase results as "candidate for review" not "should be deleted". Resources may be intentionally idle (DR, staging, warm standby).

WRONG:  "Delete these 5 disks to save $87/mo"
CORRECT: "5 detached disks identified as candidates for review. Estimated waste: $87/mo if all are unnecessary."

Rule 7: Check Protection Labels Before Flagging

Look for labels like do-not-delete, keep, protected, backup. GCP labels are always lowercase with hyphens/underscores. If found, mark as "PROTECTED -- skipped" in the output.

WRONG:  "disk-abc (labeled keep) is idle, candidate for deletion"
CORRECT: "disk-abc: PROTECTED (label: keep) -- skipped"

Rule 8: Cloud SQL activationPolicy=NEVER Means Stopped, Not Idle

Cloud SQL instances with activationPolicy=NEVER are explicitly stopped by the user. They still incur storage costs. Do NOT confuse stopped Cloud SQL with idle (running but unused) Cloud SQL.

WRONG:  "Cloud SQL my-db is idle (activationPolicy=NEVER)"
CORRECT: "Cloud SQL my-db is STOPPED (activationPolicy=NEVER). Storage cost continues: 100GiB SSD = $17/mo"

Rule 9: GKE Node Pools -- Only Flag Zero Nodes + No Autoscaler

A node pool with 0 nodes but autoscaler enabled is intentional (scale-to-zero). Only flag pools with 0 nodes AND autoscaling disabled or absent.

WRONG:  "node-pool-abc has 0 nodes, candidate for review"
CORRECT: "node-pool-abc has 0 nodes, autoscaler ENABLED (min=0, max=5) -- intentional, skipped"
CORRECT: "node-pool-def has 0 nodes, autoscaler DISABLED, initial=3. Candidate for review: may be abandoned."

Mandatory Pre-Detection Checklist

Before writing ANY idle resource analysis, verify ALL of the following:

• Project context established (gcloud config or --project)
• Protection labels checked before flagging any resource (see Rule 7)
• Cost estimates use current on-demand pricing (see pricing table below)
• Results clearly state "candidates for review" not "should be deleted" (see Rule 6)
• Each resource shows estimated monthly waste
• All costs include currency unit (USD, tax-exclusive)
• Snapshot-image cross-reference performed (see Rule 5)
• Parallel execution used for all gcloud API calls (see gcp/SKILL.md)

Idle Resources Script (get_idle_resources_gcp.sh)

DO NOT read or modify the script file. Only source and call the functions.

SETUP (at the start of your script):

source ./_skills/connections/gcp/gcp-idle-resources/scripts/get_idle_resources_gcp.sh

All functions enforce anti-hallucination rules: protection label checks, cost estimation, "candidate for review" language, TOON output format.

FUNCTION REFERENCE:

RECOMMENDED WORKFLOW (every idle resource analysis):

1. Run gcp_idle_summary for a unified view of all idle resource types with total waste estimate
2. For deeper analysis of a specific category, run the individual function
3. Always review "PROTECTED" items separately -- they were intentionally labeled

Examples:

source ./_skills/connections/gcp/gcp-idle-resources/scripts/get_idle_resources_gcp.sh

# Full idle resource scan (default project)
gcp_idle_summary

# Full scan in specific project
gcp_idle_summary --days 30 --project my-project-id

# Detached Persistent Disks only
gcp_idle_disks

# Idle Cloud SQL instances (14-day window)
gcp_idle_cloudsql --days 14

# Unused External IPs
gcp_idle_ips

# Long-stopped VMs (60-day threshold)
gcp_idle_vms_stopped --days 60

# Idle Cloud NAT
gcp_idle_nat --days 14

# Old snapshots (120-day threshold)
gcp_idle_snapshots --days 120

# Abandoned GKE node pools
gcp_idle_gke_nodepools

# Unused VPC connectors
gcp_idle_vpc_connectors --days 7

# Orphaned Filestore instances
gcp_idle_filestore --days 14

Resource Cost Reference

Approximate monthly costs in USD (tax-exclusive, us-central1). Use to validate waste estimates.

Note: All prices are TAX-EXCLUSIVE. Console shows tax-inclusive totals. See gcp/SKILL.md for VAT/tax handling.

For resources not listed above, use get_gcp_cost from the gcp/ skill.

GCP Detection Commands Reference

Quick reference for the gcloud CLI commands used to detect each idle resource type.

Cloud Monitoring Metrics Used

CRITICAL: alignment-period MUST be >= 60 seconds when using aligners other than ALIGN_NONE.

Common Errors

Output Format

Present results as a structured report:

Gcp Idle Resources Report
═════════════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

Counter-Rationalizations