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PASSEDcloud / aws_ecs
AWS: ECS Service Stuck at 0 Running Tasks — Insufficient Memory
An ECS Fargate service cannot start any tasks because the task memory reservation exceeds the available capacity.
Pattern
AWS_CLOUD
Expected: AWS_ECS_FAILURE
Severity
HIGH
Confidence
68%
Remediation
Auto-Heal
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | AWS_ECS_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 ECS Fargate service 'api'. Task definition requires 8GB memory. Fargate capacity: available. But memory reservation conflicts with other tasks. Service stuck at 0/4.
Injected Error Messages (1)
AWS ECS service stuck — service 'api-prod' at 0/4 running tasks, task start failing: 'reason: RESOURCE:MEMORY', task definition 8192MB but insufficient cluster memory available
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_ECS_FAILURE)
- Severity: HIGH (expected CRITICAL)
Tested: 2026-04-02Monitors: 1 | Incidents: 1Test ID: cmnhnr8vb09bglig70dl09e29