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PASSEDnetwork / proxy_failure
Reverse Proxy 502 — All Backend Servers Health Check Failed
HAProxy is returning 502 Bad Gateway because all backend servers failed their health checks simultaneously after a coordinated deployment.
Pattern
CONNECTION_REFUSED
Expected: PROXY_FAILURE
Severity
CRITICAL
Confidence
68%
Remediation
Auto-Heal
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | PROXY_FAILURE | CONNECTION_REFUSED | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | N/A | None | |
| Cascade Escalation | N/A | No | |
| Remediation | — | Auto-Heal — Corax resolves autonomously |
Scenario Conditions
HAProxy 2.8. Backend pool 'api-servers' with 4 servers. All 4 deployed at same time. New version crashes on startup. HAProxy health checks: all DOWN.
Injected Error Messages (1)
HAProxy 502 — all 4 backend servers in pool 'api-servers' DOWN, health check failing on all: connection refused, simultaneous deployment crashed all backends, 100% error rate
Neural Engine Root Cause Analysis
Connection refused — service is likely crashed or not listening on the expected port.
Remediation Plan
Restart the target service. If recurring, check for memory leaks or crash loops.
Improvements Applied
- Pattern classified as CONNECTION_REFUSED (expected PROXY_FAILURE)
Tested: 2026-04-02Monitors: 1 | Incidents: 1Test ID: cmnhnoopv0021lig7vhgx8pkr