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PASSEDcloud / aws_alb
AWS: ALB Target Group All Targets Unhealthy
All targets in an ALB target group are failing health checks. ALB returning 502 to all clients. Health check path changed during deployment.
Pattern
AWS_CLOUD
Expected: AWS_ALB_FAILURE
Severity
HIGH
Confidence
68%
Remediation
Auto-Heal
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | AWS_ALB_FAILURE | AWS_CLOUD | |
| Severity Assessment | CRITICAL | HIGH | |
| Incident Correlation | N/A | None | |
| Cascade Escalation | N/A | No | |
| Remediation | — | Auto-Heal — Corax resolves autonomously |
Scenario Conditions
AWS ALB 'prod-alb'. Target group 'api-tg' with 4 targets. Health check path changed from /health to /api/health (doesn't exist). All 4 targets: unhealthy.
Injected Error Messages (1)
AWS ALB 502 — all 4 targets in target group 'api-tg' unhealthy, health check path '/api/health' returning 404, health check changed during deployment, ALB returning 502 to all clients
Neural Engine Root Cause Analysis
AWS cloud infrastructure event detected — an EC2 instance may be unreachable or in a stopped state, an RDS database is experiencing issues, a load balancer has unhealthy targets, or a Lambda function is failing. AWS service disruptions can cascade across dependent resources and affect application availability.
Remediation Plan
1. Check the AWS Health Dashboard and Personal Health Dashboard for any active service events.
2. For EC2 issues, check instance status checks (system and instance), review CloudWatch metrics, and check VPC security group rules.
3. For RDS, verify database instance status, check storage and connection limits, and review slow query logs.
4. For ELB issues, check target group health checks and verify backend instances are responding.
5. For Lambda, review CloudWatch Logs for invocation errors and check IAM permissions and VPC connectivity.
Improvements Applied
- Pattern classified as AWS_CLOUD (expected AWS_ALB_FAILURE)
- Severity: HIGH (expected CRITICAL)
Tested: 2026-04-02Monitors: 1 | Incidents: 1Test ID: cmnhnr8vb09bhlig7tkwl27cp