MisconfDoctor: Diagnosing misconfiguration via log-based configuration testing

As software configurations continue to grow in complexity, misconfiguration has become one of major causes of software failure. Software configuration errors can have catastrophic consequences, seriously affecting the normal use of software and quality of service. And misconfiguration diagnosis faces many challenges, such as path-explosion problems and incomplete statistical data. Our study of the log that is generated in response to misconfigurations by six widely used pieces of software highlights some interesting characteristics. These observations have influenced the design of MisconfDoctor, a misconfiguration diagnosis tool via log-based configuration testing. Through comprehensive misconfiguration testing, MisconfDoctor first extracts log features for every misconfiguration and builds a feature database. When a system misconfiguration occurs, MisconfDoctor suggests potential misconfigurations by calculating the similarity of the new exception log to the feature database. We use manual and real-world error cases from Httpd, MySQL and PostgreSQL in order to evaluate the effectiveness of the tool. Experimental results demonstrate that the tool's accuracy reaches 85% when applied to manual-error cases, and 78% for real-world cases.