Ocasta: Clustering Configuration Settings For Error Recovery

TL;DR

Ocasta is a system that clusters dependent configuration settings based on application access patterns, enabling effective repair of multi-setting configuration errors without needing source code access.

Contribution

It introduces a novel clustering approach for dependent configuration settings that improves diagnosis and repair of complex configuration errors.

Findings

Achieved 88.6% accuracy in identifying configuration clusters

Successfully repaired all tested configuration errors in 11 minutes on average

User study shows Ocasta is easy to use and more efficient than manual troubleshooting

Abstract

Effective machine-aided diagnosis and repair of configuration errors continues to elude computer systems designers. Most of the literature targets errors that can be attributed to a single erroneous configuration setting. However, a recent study found that a significant amount of configuration errors require fixing more than one setting together. To address this limitation, Ocasta statistically clusters dependent configuration settings based on the application's accesses to its configuration settings and utilizes the extracted clustering of configuration settings to fix configuration errors involving more than one configuration settings. Ocasta treats applications as black-boxes and only relies on the ability to observe application accesses to their configuration settings. We collected traces of real application usage from 24 Linux and 5 Windows desktops computers and found that Ocasta is able to correctly identify clusters with 88.6% accuracy. To demonstrate the effectiveness of Ocasta, we evaluated it on 16 real-world configuration errors of 11 Linux and Windows applications. Ocasta is able to successfully repair all evaluated configuration errors in 11 minutes on average and only requires the user to examine an average of 3 screenshots of the output of the application to confirm that the error is repaired. A user study we conducted shows that Ocasta is easy to use by both expert and non-expert users and is more efficient than manual configuration error troubleshooting.