Finops Cost Optimization

OCI FinOps - Expert Knowledge

🏗️ Use OCI Landing Zone Terraform Modules

Don't reinvent the wheel. Use oracle-terraform-modules/landing-zone for cost-optimized infrastructure.

Landing Zone solves:

• ❌ Bad Practice #3: Internet breakout from spoke networks (Egress cost waste $3k-5k/month; Landing Zone uses hub-spoke with centralized NAT/Firewall)
• ❌ Bad Practice #8: Creating your own Terraform modules (Maintenance cost; Landing Zone is Oracle-maintained, CIS-certified, no technical debt)
• ❌ Bad Practice #10: No monitoring (Blind spending; Landing Zone auto-configures budget alerts, usage notifications, and cost tracking)

This skill provides: Cost optimization strategies, hidden cost traps, and savings calculations for resources deployed WITHIN a Landing Zone.

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⚠️ OCI CLI/API Knowledge Gap

You don't know OCI CLI commands or OCI API structure.

Your training data has limited and outdated knowledge of:

• OCI CLI syntax and parameters (updates monthly)
• OCI API endpoints and request/response formats
• Cost Management CLI operations (oci usage-api)
• Current OCI pricing (changes frequently)
• Universal Credits consumption rates and SKUs

When OCI operations are needed:

1. Use exact CLI commands from skill references
2. Do NOT guess OCI CLI syntax or parameters
3. Do NOT assume current pricing - always verify
4. Reference official Oracle pricing calculator

What you DO know:

• General cloud cost optimization principles
• FinOps frameworks and methodologies
• Resource right-sizing concepts

This skill bridges the gap by providing current OCI-specific cost traps and optimization patterns.

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You are an OCI cost optimization expert. This skill provides knowledge Claude lacks: hidden cost traps, Universal Credits gotchas, exact savings calculations, free tier maximization, and OCI-specific billing nuances.

NEVER Do This

❌ NEVER ignore orphaned boot volumes (silent cost drain)

# Default OCI behavior: Boot volumes PRESERVED after instance termination
oci compute instance terminate --instance-id  --force
# Instance deleted, but boot volume remains (charges continue!)

Cost trap:
- Boot volume: 50 GB × $0.025/GB/mo = $1.25/month per instance
- 20 terminated test instances = $25/month wasted
- Over 1 year: $300 wasted on deleted instances

# RIGHT - explicitly delete boot volume
oci compute instance terminate \
  --instance-id  \
  --preserve-boot-volume false  # Critical flag!

# Or in Terraform:
resource "oci_core_instance" "dev" {
  preserve_boot_volume = false  # Must set explicitly
}

Cleanup strategy: Monthly audit for unattached boot volumes older than 7 days

❌ NEVER forget reserved public IPs cost money when unattached

Cost: $0.01/hour = $7.30/month per IP

# Common mistake: Reserve IP, detach from instance, forget to release
oci network public-ip create --lifetime RESERVED
# Later: delete instance but IP remains reserved (charges continue)

Wasted cost example:
- 5 old reserved IPs from deleted instances
- 5 × $7.30/month = $36.50/month waste
- Over 1 year: $438 wasted

# RIGHT - use ephemeral IPs for temporary resources
oci network public-ip create --lifetime EPHEMERAL
# Auto-deleted when instance terminated

# Or release reserved IPs explicitly
oci network public-ip delete --public-ip-id 

Detection: List reserved IPs without instance attachment

❌ NEVER assume stopped resources = zero cost

Stopped Autonomous Database:
✓ Compute: Zero cost (stopped)
✗ Storage: $0.025/GB/mo continues
✗ Backups: Retention charges continue

Example: 1 TB ADB stopped for 30 days
Storage: 1000 GB × $0.025 = $25/month (charged!)

Stopped Compute Instance:
✓ Compute: Zero cost
✗ Boot volume: $0.025/GB/mo continues
✗ Block volumes: $0.025/GB/mo continues
✗ Reserved IP (if attached): $7.30/month continues

# Better for long-term idle (>30 days): TERMINATE + backup
# Restore from backup when needed

Rule: Stopped = compute paused, storage still charged

❌ NEVER ignore data egress costs (surprise bills)

OCI egress pricing:
- First 10 TB/month: FREE
- 10-50 TB: $0.0085/GB
- 50+ TB: Contact sales for discount

# Common mistake: Large data export
oci os object bulk-download --bucket-name backups --download-dir /local
# Downloading 15 TB = 5 TB chargeable × $0.0085/GB = $42,500 surprise!

# Cheaper alternatives:
1. Use OCI FastConnect (fixed cost, unlimited egress)
2. Download within same region (free between OCI services)
3. Export to another OCI region first (inter-region = free)

Cost comparison (15 TB export):
- Internet egress: $42,500
- FastConnect (1 Gbps): $1,100/month flat rate
- Breakeven: 130 GB/month egress

Gotcha: Egress is FREE between OCI regions (intra-Oracle network)

❌ NEVER enable NAT Gateway without understanding costs

NAT Gateway pricing:
- Gateway itself: $0.01/hour = $7.30/month
- Data processed: $0.01/GB

# Mistake: Use NAT Gateway for high-traffic apps
Example: Application with 5 TB/month outbound traffic
- Gateway: $7.30/month
- Data: 5000 GB × $0.01 = $50/month
- Total: $57.30/month

# Cheaper alternative: Public IP on instance (ephemeral IP = free)
Cost: $0/month for egress  \
  --type ACTUAL \
  --threshold 50 \
  --recipients "team@example.com"

oci budgets alert-rule create \
  --budget-id  \
  --type ACTUAL \
  --threshold 80 \
  --recipients "team@example.com,manager@example.com"

oci budgets alert-rule create \
  --budget-id  \
  --type ACTUAL \
  --threshold 90 \
  --recipients "team@example.com,manager@example.com,finance@example.com"

oci budgets alert-rule create \
  --budget-id  \
  --type ACTUAL \
  --threshold 100 \
  --recipients "team@example.com,manager@example.com,finance@example.com"

Alert strategy:
50%: FYI to team (informational)
80%: Action required (investigate spike)
90%: Escalation to management
100%: Finance involved (budget exceeded)

Gotcha: Budgets are ALERTING only, not enforcement (cannot block spending)

Hidden Cost Detection

Monthly audit checklist:

# 1. Orphaned boot volumes (cost trap #1)
oci bv boot-volume list --all --lifecycle-state AVAILABLE \
  | grep -v "attached-instance"

# 2. Unattached block volumes
oci bv volume list --all --lifecycle-state AVAILABLE

# 3. Reserved IPs without instance
oci network public-ip list --scope REGION --lifetime RESERVED

# 4. Stopped instances with volumes
oci compute instance list --lifecycle-state STOPPED

# 5. Old snapshots/backups
oci bv backup list --all \
  | jq '.data[] | select(.["time-created"] < "2024-01-01")'

# 6. Unused load balancers (no backends)
oci lb load-balancer list --all

# 7. Empty Object Storage buckets
oci os bucket list --all --fields approximateCount,approximateSize

Estimated monthly savings: $100-500 for typical tenancy (cleanup waste)

Progressive Loading References

OCI Cost Management CLI

WHEN TO LOAD [oci-cost-cli.md](references/oci-cost-cli.md):

• Setting up budgets and alert rules
• Querying usage reports via CLI
• Managing service limits and quotas
• Implementing tagging for cost allocation
• Downloading detailed cost reports

Do NOT load for:

• Quick cost calculations (tables and examples above)
• Understanding cost traps (NEVER list above)
• Shape pricing comparisons (covered above)

Official Oracle Documentation Sources

Primary References (200+ official sources scraped):

• Billing and Cost Management Overview
• Cost Reports Overview
• Budgets Overview
• Cost Management Best Practices
• OCI FinOps Hub
• Cloud Advisor (Cost Optimization)

Note: All cost calculations, traps, and gotchas in this skill are derived from these official sources and A-Team Oracle blog

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When to Use This Skill

• Unexpected bills: Investigating charges, finding cost spikes
• Budget planning: Estimating costs, setting budgets, forecasting
• Cost optimization: Right-sizing, waste reduction, shape migration
• Free tier: Maximizing always-free usage, avoiding over-provisioning
• Universal Credits: Commitment planning, credit allocation
• Cost allocation: Showback, chargeback, shared resource costs
• Savings calculations: Comparing options, ROI analysis

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: acedergren
• Source: acedergren/oci-agent-skills
• License: MIT

Install and usage instructions live in the source repository linked above.