System configuration languages provide powerful abstractions that simplify managing large-scale, networked systems. Thousands of organizations now use configuration languages, such as Puppet. However, specifications written in configuration languages can have bugs and the shell remains the simplest way to debug a misconfigured system. Unfortunately, it is unsafe to use the shell to fix problems when a system configuration language is in use: a fix applied from the shell may cause the system to drift from the state specified by the configuration language. Thus, despite their advantages, configuration languages force system administrators to give up the simplicity and familiarity of the shell.
This paper presents a synthesis-based technique that allows administrators to use configuration languages and the shell in harmony. Administrators can fix errors using the shell and the technique automatically repairs the higher-level specification written in the configuration language. The approach (1) produces repairs that are consistent with the fix made using the shell; (2) produces repairs that are maintainable by minimizing edits made to the original specification; (3) ranks and presents multiple repairs when relevant; and (4) supports all shells the administrator may wish to use. We implement our technique for Puppet, a widely used system configuration language, and evaluate it on a suite of benchmarks under 42 repair scenarios. The top-ranked repair is selected by humans 76% of the time and the human-equivalent repair is ranked 1.31 on average.
@inproceedings{Weiss17ase,
author = {Aaron Weiss and Arjun Guha and Yuriy Brun},
title = {\href{http://people.cs.umass.edu/brun/pubs/pubs/Weiss17ase.pdf}{Tortoise: {Interactive} System Configuration Repair}},
booktitle = {Proceedings of the 32nd IEEE/ACM International Conference on
Automated Software Engineering (ASE)},
venue = {ASE},
month = {October/November},
year = {2017},
date = {31--2},
address = {Urbana-Champaign, IL, USA},
pages = {625--636},
doi = {10.1109/ASE.2017.8115673},
note = {\href{https://doi.org/10.1109/ASE.2017.8115673}{DOI: 10.1109/ASE.2017.8115673},
arXiv: \href{https://arxiv.org/abs/1709.05366}{abs/1709.05366}},
fundedBy = {NSF CNS-1413985, NSF CCF-1453474, NSF CCF-1564162, NSF CCF-1717636, NSF CNS-1744471},
accept = {$\frac{65}{314} \approx 21\%$},
abstract = {<p>System configuration languages provide powerful abstractions that simplify
managing large-scale, networked systems. Thousands of organizations now use
configuration languages, such as Puppet. However, specifications written in
configuration languages can have bugs and the shell remains the simplest way
to debug a misconfigured system. Unfortunately, it is unsafe to use the shell
to fix problems when a system configuration language is in use: a fix applied
from the shell may cause the system to drift from the state specified by the
configuration language. Thus, despite their advantages, configuration
languages force system administrators to give up the simplicity and
familiarity of the shell.</p>
<p>This paper presents a synthesis-based technique that allows administrators to
use configuration languages and the shell in harmony. Administrators can fix
errors using the shell and the technique automatically repairs the
higher-level specification written in the configuration language. The
approach (1) produces repairs that are consistent with the fix made using the
shell; (2) produces repairs that are maintainable by minimizing edits made to
the original specification; (3) ranks and presents multiple repairs when
relevant; and (4) supports all shells the administrator may wish to use. We
implement our technique for Puppet, a widely used system configuration
language, and evaluate it on a suite of benchmarks under 42 repair scenarios.
The top-ranked repair is selected by humans 76% of the time and the
human-equivalent repair is ranked 1.31 on average.</p>},
}