lighthouse-incident

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Your Submission

{
  "root_cause": "analysis_memory_leak",
  "methodology": "1) Fetched system status and topology to understand dependencies. 2) Retrieved anomaly timeline from logs API - identified earliest event (analysis MEMORY_USAGE_HIGH 18:00:15). 3) Got error summary - analysis had most critical/error events. 4) Correlated events across subsystems - confirmed analysis OOM preceded preprocessing/ingestion failures. 5) Consulted memory-leak-recovery runbook before acting. 6) Executed recovery steps in strict order per runbook: restart_workers, drain_preprocessing_backlog, resume_normal_processing, restore_rate_limit. 7) Verified via metrics and system status.",
  "failure_chain": [
    "analysis",
    "preprocessing",
    "results-store",
    "ingestion",
    "archive",
    "query-gateway"
  ],
  "incident_report": "## Executive Summary\n\nP1 incident INC-147693: LIGHTHOUSE pipeline experienced cascading failures. Root cause: analysis subsystem memory leak leading to OOM kills. Recovery completed in 4 steps per runbook. Ingestion, preprocessing, and analysis restored to healthy status.\n\n## Root Cause Analysis\n\n**Root cause:** analysis_memory_leak\n\n**Evidence:** Timeline shows analysis first anomaly at 18:00:15 (MEMORY_USAGE_HIGH). Sequential OOM kills (18:45, 19:30, 19:59), then WORKER_RESTART_LOOP with explicit 'memory leak suspected' (20:01:22). All workers OOM-killed by 20:29:42. Downstream effects: preprocessing queue backed up (analysis stopped consuming), ingestion throttled (backpressure).\n\n## Impact Assessment\n\n- Analysis: 100% worker failure, throughput dropped to 3%\n- Preprocessing: queue depth critical (47k+ observations)\n- Ingestion: adaptive throttle triggered (60%)\n- Results-store: replication lag\n- Archive: segment merge backlog\n- Query-gateway: connection retries\n\n## Recovery Timeline\n\n1. restart_workers (analysis) - workers restarted with conservative memory limits\n2. drain_preprocessing_backlog (analysis) - backlog drained\n3. resume_normal_processing (preprocessing) - full rate restored\n4. restore_rate_limit (ingestion) - ingestion throttle removed\n\nPost-recovery: ingestion, preprocessing, analysis healthy. Results-store and archive still strained (may resolve as data flows).\n\n## Prevention Recommendations\n\n- Run memory profiling on analysis workers regularly\n- Configure per-worker memory limits with headroom\n- Add alerting on MEMORY_USAGE_HIGH before OOM\n- Consider circuit breaker for analysis to fail fast before cascade\n",
  "recovery_script": "#!/usr/bin/env python3\n# LIGHTHOUSE Recovery Script\n# Implement automated recovery based on your investigation\n# Root cause: analysis_memory_leak\n\nimport subprocess\nimport sys\n\ndef recover(api_base: str, agent_key: str) -> bool:\n    headers = {\n        \"Authorization\": f\"Bearer {agent_key}\",\n        \"Content-Type\": \"application/json\"\n    }\n    steps = [\n        (\"analysis\", \"restart_workers\", {}),\n        (\"analysis\", \"drain_preprocessing_backlog\", {}),\n        (\"preprocessing\", \"resume_normal_processing\", {}),\n        (\"ingestion\", \"restore_rate_limit\", {})\n    ]\n    for subsystem, action, params in steps:\n        body = {\"subsystem\": subsystem, \"action\": action, \"params\": params}\n        r = subprocess.run(\n            [\"curl\", \"-s\", \"-X\", \"POST\", \"-H\", headers[\"Authorization\"], \"-H\", headers[\"Content-Type\"], \"-d\", str(body).replace(\"'\", '\"'), f\"{api_base}/system/recover\"],\n            capture_output=True, text=True\n        )\n        if r.returncode != 0:\n            sys.stderr.write(f\"Step {subsystem}/{action} failed\")\n            return False\n    return True\n\nif __name__ == \"__main__\":\n    recover(sys.argv[1], sys.argv[2])\n",
  "root_cause_evidence": "Anomaly timeline shows analysis subsystem first with MEMORY_USAGE_HIGH (18:00:15), followed by OOM_KILL events (Worker-2 at 18:45:27, 19:30:25; Worker-0 at 19:59:31), then WORKER_RESTART_LOOP — 'memory leak suspected' (20:01:22 CRITICAL), and 'All workers OOM-killed' (20:29:42). Error summary: analysis had 4 errors, 2 critical, unique codes OOM_KILL, WORKER_RESTART_LOOP, MEMORY_USAGE_HIGH. Earliest anomaly across all subsystems was analysis at 18:00:15. Correlated events show analysis OOM preceded preprocessing QUEUE_DEPTH_CRITICAL (20:31:13) and ingestion INGESTION_THROTTLE (22:09:58). Propagation: analysis failed -> preprocessing queue backed up (analysis stopped consuming) -> ingestion throttled (backpressure).",
  "recovery_actions_taken": [
    {
      "action": "restart_workers",
      "params": {},
      "result": "success",
      "subsystem": "analysis"
    },
    {
      "action": "drain_preprocessing_backlog",
      "params": {},
      "result": "success",
      "subsystem": "analysis"
    },
    {
      "action": "resume_normal_processing",
      "params": {},
      "result": "success",
      "subsystem": "preprocessing"
    },
    {
      "action": "restore_rate_limit",
      "params": {},
      "result": "success",
      "subsystem": "ingestion"
    }
  ],
  "failure_chain_reasoning": "Analysis failed first due to memory leak (OOM kills). Analysis consumes from preprocessing; when analysis workers died, preprocessing queue backed up (QUEUE_DEPTH_CRITICAL 20:31:13). Analysis writes to results-store; replication lag appeared (18:20:09) as analysis output slowed. Backpressure propagated upstream: preprocessing sent BACKPRESSURE_SIGNAL (20:49:30), ingestion throttled (22:09:58). Archive and query-gateway showed secondary effects (SEGMENT_MERGE_SLOW, CONNECTION_RETRY) from reduced pipeline throughput."
}