Back to All Scenarios
PASSEDcloud / aws_lambda_cold_start
AWS Lambda Cold Start Timeout Spike
After a Lambda function deployment, cold start times spike from 2 seconds to 28 seconds due to a new heavy SDK dependency. API Gateway returns 504 Gateway Timeout for cold-start invocations. Provisioned concurrency was removed to save costs last month.
Pattern
AWS_CLOUD
Severity
CRITICAL
Confidence
85%
Remediation
Auto-Heal
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | AWS_CLOUD | AWS_CLOUD | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | Yes | 16 linked | |
| Cascade Escalation | N/A | No | |
| Remediation | — | Auto-Heal — Corax resolves autonomously |
Scenario Conditions
AWS Lambda (Node.js 20 runtime). API Gateway REST API. Function size: 250MB (new AWS SDK v3 bundling issue). Cold start: 28s (timeout: 29s). Provisioned concurrency: 0. Average 200 invocations/minute.
Injected Error Messages (2)
AWS Lambda cold start timeout — function 'order-processor' Init Duration: 28,400ms (timeout: 29,000ms), CloudWatch: 15% of invocations timing out, error: Task timed out after 29.00 seconds, deployment artifact size: 250MB, memory: 1024MB
API Gateway 504 errors spiking — 15% of requests to /orders returning HTTP 504 Gateway Timeout, Lambda integration timeout, X-Ray trace showing 28s cold start initialization, CloudWatch alarm: 5xx error rate above threshold
Neural Engine Root Cause Analysis
The AWS Lambda function 'order-processor' is experiencing severe cold start performance issues with initialization taking 28.4 seconds against a 29-second timeout. The root cause is likely the extremely large deployment artifact (250MB) combined with potentially insufficient memory allocation (1024MB) and inefficient initialization code. With 15% of invocations timing out and 7 correlated incidents in the same timeframe, this indicates a systemic performance degradation affecting multiple services, possibly due to recent deployment changes or resource constraints.
Remediation Plan
1. Immediately increase Lambda memory allocation from 1024MB to 3008MB to improve CPU allocation and reduce cold start times. 2. Enable provisioned concurrency for 2-5 instances to eliminate cold starts for critical traffic. 3. Investigate deployment artifact optimization - consider code splitting, removing unused dependencies, and implementing Lambda layers. 4. Review recent deployments that may have introduced performance regressions. 5. Monitor CloudWatch metrics for improvement and adjust provisioned concurrency based on traffic patterns.
Tested: 2026-03-30Monitors: 2 | Incidents: 2Test ID: cmncjkmgi0283obqen9nxnj5q