LogBERT: Log Anomaly Detection via BERT

Abstract

When systems break down, administrators usually check the produced logs to diagnose the failures. Nowadays, systems grow larger and more complicated. It is labor-intensive to manually detect abnormal behaviors in logs. Therefore, it is necessary to develop an automated anomaly detection on system logs. Automated anomaly detection not only identifies malicious patterns promptly but also requires no prior domain knowledge. Many existing log anomaly detection approaches apply natural language models such as Recurrent Neural Network (RNN) to log analysis since both are based on sequential data. The proposed model, LogBERT, a BERT-based neural network, can capture the contextual information in log sequences. LogBERT is trained on normal log data considering the scarcity of labeled abnormal data in reality. Intuitively, LogBERT learns normal patterns in training data and flags test data that are deviated from prediction as anomalies. We compare LogBERT with four traditional machine learning models and two deep learning models in terms of precision, recall, and F1 score on three public datasets, HDFS, BGL, and Thunderbird. Overall, LogBERT outperforms the state-of-art models for log anomaly detection