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PASSEDcache / fd_exhaustion

Varnish 7.5 File Descriptor Limit Reached on AlmaLinux 9

Varnish 7.5 has exhausted its file descriptor limit. Cannot accept new connections or open new files. Service functionality severely degraded.

Pattern
CONNECTION_REFUSED
Severity
CRITICAL
Confidence
68%
Remediation
Auto-Heal

Test Results

MetricExpectedActualResult
Pattern RecognitionCONNECTION_REFUSEDCONNECTION_REFUSED
Severity AssessmentHIGHCRITICAL
Incident CorrelationN/ANone
Cascade EscalationN/ANo
RemediationAuto-Heal — Corax resolves autonomously

Scenario Conditions

AlmaLinux 9. Varnish 7.5 at 43722/43728 file descriptors. Connection leak detected. ulimit -n set to 43728 (default, not tuned for production).

Injected Error Messages (1)

Varnish 7.5 on AlmaLinux 9 — 43722/43728 FDs used, 'Too many open files', connection refused on new requests, varnishd leaking file descriptors at 69/min

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

  • Severity: CRITICAL (expected HIGH)
Tested: 2026-04-02Monitors: 1 | Incidents: 1Test ID: cmnhnpzzh04ralig7b09c1cqh