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Main Authors: Pham, Luan, Nicolet, Victor, Dodds, Joey, Guan, Hui, Kroening, Daniel
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.00936
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author Pham, Luan
Nicolet, Victor
Dodds, Joey
Guan, Hui
Kroening, Daniel
author_facet Pham, Luan
Nicolet, Victor
Dodds, Joey
Guan, Hui
Kroening, Daniel
contents Anomaly detection and localization (ADL) is critical for maintaining reliability and availability in cloud systems. Recent ADL developments focus on metric and log data, leaving event data unexplored. To address this gap, we propose EventADL, the first open-box event-based ADL framework for cloud-based service systems. To motivate the design of our framework, we conduct a systematic analysis on 520 real-world incidents, and provide insights into how anomalies and their root causes manifest through event data. EventADL has three phases: offline training, online anomaly detection, and root cause localization. During the training phase, EventADL first learns Event Semantic Patterns (ESPs), which capture normal interactions between system entities using historical event data, and then learns Event Frequency Patterns (EFPs), which capture the normal frequency of known ESPs. In the online anomaly detection phase, any data in the event stream that deviates significantly from either pattern is identified as anomalous. For localization, EventADL constructs an Intervention Graph that models the relationships between recent system interactions and the detected anomalies for automatic root cause localization. The framework is designed to operate efficiently with unlabeled data and to produce interpretable anomalies with their corresponding root causes. Our evaluation on three real cloud service systems and two real-world incidents demonstrates that EventADL outperforms existing methods, achieving F1-scores of at least 90% for anomaly detection and 100% top-3 accuracy in root cause localization.
format Preprint
id arxiv_https___arxiv_org_abs_2605_00936
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle EventADL: Open-Box Anomaly Detection and Localization Framework for Events in Cloud-Based Service Systems
Pham, Luan
Nicolet, Victor
Dodds, Joey
Guan, Hui
Kroening, Daniel
Machine Learning
Artificial Intelligence
Anomaly detection and localization (ADL) is critical for maintaining reliability and availability in cloud systems. Recent ADL developments focus on metric and log data, leaving event data unexplored. To address this gap, we propose EventADL, the first open-box event-based ADL framework for cloud-based service systems. To motivate the design of our framework, we conduct a systematic analysis on 520 real-world incidents, and provide insights into how anomalies and their root causes manifest through event data. EventADL has three phases: offline training, online anomaly detection, and root cause localization. During the training phase, EventADL first learns Event Semantic Patterns (ESPs), which capture normal interactions between system entities using historical event data, and then learns Event Frequency Patterns (EFPs), which capture the normal frequency of known ESPs. In the online anomaly detection phase, any data in the event stream that deviates significantly from either pattern is identified as anomalous. For localization, EventADL constructs an Intervention Graph that models the relationships between recent system interactions and the detected anomalies for automatic root cause localization. The framework is designed to operate efficiently with unlabeled data and to produce interpretable anomalies with their corresponding root causes. Our evaluation on three real cloud service systems and two real-world incidents demonstrates that EventADL outperforms existing methods, achieving F1-scores of at least 90% for anomaly detection and 100% top-3 accuracy in root cause localization.
title EventADL: Open-Box Anomaly Detection and Localization Framework for Events in Cloud-Based Service Systems
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2605.00936