AWS Budgets: Proactively Prevent Cost Overruns with Budget Alerts
Learn how to set up AWS Budgets for cost thresholds, receive alerts, and configure automatic actions to control AWS spending.
Related Exam Domains
- Domain 4: Design Cost-Optimized Architectures
Key Takeaway
AWS Budgets sets cost/usage budgets, sends email/SNS alerts when thresholds are reached, and can automatically execute cost control actions. First 2 budgets are free, and alerts can be based on actual or forecasted costs.
Exam Tip
Exam Essential: "Budget setting + alerts = AWS Budgets", "Cost visualization + analysis = Cost Explorer"
What is AWS Budgets?
A service for setting and monitoring budgets on AWS costs and usage.
[AWS Budgets]
│
├── Budget Set: $500/month
│
├── Alert 1: Actual cost 80% ($400) reached → Email
├── Alert 2: Actual cost 100% ($500) reached → SNS
├── Alert 3: Forecasted cost exceeds 100% → Email + SNS
│
└── Auto Action: Block EC2 launches via IAM policy
Budget Types
| Type | Description | Use Case |
|---|---|---|
| Cost Budget | Monitor spending amount | "Keep under $1,000/month" |
| Usage Budget | Monitor service usage | "Keep EC2 hours under 500h" |
| RI Utilization Budget | Monitor RI utilization | "Maintain RI usage above 80%" |
| RI Coverage Budget | Monitor RI coverage | "Cover 70% of EC2 with RI" |
| Savings Plans Utilization | Monitor SP utilization | "Keep SP usage above 90%" |
| Savings Plans Coverage | Monitor SP coverage | "Cover 60% of compute with SP" |
Alert Configuration
Alert Thresholds
Budget: $500/month
Alert Configuration:
┌─────────────────────────────────────────┐
│ $500 ─────────────── 100% ── Alert 2 │
│ $400 ─────────────── 80% ── Alert 1 │
│ │
│ ████████████████░░░░ Current: $350(70%)│
│ │
│ Forecast: $520 ──── 104% ── Alert 3 │
└─────────────────────────────────────────┘
Alert Types
| Type | Trigger | When to Use |
|---|---|---|
| Actual | Actual cost reaches threshold | Monitor current spending |
| Forecasted | Forecasted cost expected to exceed threshold | Proactive response |
Alert Delivery Methods
| Method | Description |
|---|---|
| Direct delivery to up to 10 recipients | |
| Amazon SNS | Deliver to SNS topic (can trigger Lambda) |
| AWS Chatbot | Notify Slack, Teams |
Budget Actions
Automatically execute cost control actions when budget thresholds are exceeded.
Supported Actions
| Action | Description |
|---|---|
| Apply IAM Policy | Attach Deny policy to users/roles |
| Apply SCP | Attach SCP to Organizations accounts |
| Stop EC2/RDS | Stop specific instances |
Auto-response flow when budget exceeded:
[Cost 80% reached] → Email alert
[Cost 100% reached] → SNS alert + Apply IAM policy
└── Attach EC2 launch block policy
[Cost 120% exceeded] → Stop EC2/RDS instances
Exam Tip
Budget Actions: Beyond alerts, enables automatic actions like IAM policies, SCPs, and instance stopping.
Budget Templates
AWS provides predefined templates for quick setup.
| Template | Alert Conditions |
|---|---|
| Monthly Cost Budget | Actual 85%, 100%, Forecasted 100% |
| Daily Savings Plans Coverage | Coverage below 80% |
| Daily RI Utilization | Utilization below 80% |
| Monthly Cost Budget (Email) | Budget 85%, 100% |
Budgets vs CloudWatch Billing Alarms
| Feature | AWS Budgets | CloudWatch Billing Alarms |
|---|---|---|
| Budget Types | Cost, Usage, RI, SP | Cost only |
| Forecast Alerts | Yes | No |
| Auto Actions | Yes (IAM/SCP/Instances) | No |
| Filtering | Service, tag, account, etc. | Limited |
| Cost | 2 free, then $0.02/day | Free |
| Setup Region | Global | us-east-1 only |
Exam Tip
Budgets Recommended: More feature-rich than CloudWatch Billing Alarms. On exams, "cost alerts" often means Budgets is the answer.
Cost Management Tool Selection Guide
Cost Management Purpose:
│
▼
Want to visualize/analyze costs?
│
Yes → [Cost Explorer]
│
No
│
▼
Want to set budgets and receive alerts?
│
Yes → [AWS Budgets]
│
No
│
▼
Want detailed usage in CSV/Parquet?
│
Yes → [Cost and Usage Report]
│
No
│
▼
Want overall optimization recommendations?
│
Yes → [Trusted Advisor]
Pricing Structure
| Item | Cost |
|---|---|
| First 2 budgets | Free |
| Additional budgets | $0.02/day/budget (~$0.62/month) |
| Budget Actions | Free |
| Budget Reports | $0.01/report delivery |
SAA-C03 Exam Focus Points
- ✅ Cost Alerts: "Budget overrun alert = AWS Budgets"
- ✅ Forecast Alerts: "Proactive alerts based on forecasted costs"
- ✅ Auto Actions: "Auto-execute IAM policy, SCP, instance stop"
- ✅ vs Cost Explorer: "Analysis = Cost Explorer, Alerts = Budgets"
- ✅ RI/SP Monitoring: "Monitor RI utilization, SP coverage"
Exam Tip
Sample Exam Question: "Automatically block EC2 instance launches when the dev team's monthly AWS costs exceed $500?" → Answer: Set cost budget in AWS Budgets + Budget Actions to auto-attach IAM Deny policy
Frequently Asked Questions (FAQ)
Q: Are Budgets alerts real-time?
No. There may be delays in cost data updates. Costs may exceed budget before receiving alerts, so set conservative thresholds (e.g., 80%).
Q: Can I get alerts for Free Tier usage?
Yes. Set usage budgets to receive alerts when approaching Free Tier limits. AWS also provides separate Free Tier usage alerts.
Q: Can I set budgets per member account in Organizations?
Yes. From the management account, you can set per-member-account budgets with different thresholds and alerts.
Q: Are Budget Actions executed automatically?
You can choose automatic or approval-required execution. Approval-required is recommended for production environments.
Q: What happens if I change the budget mid-month?
The new budget amount applies from the change point. Previously incurred costs were already alerted based on the old budget.