AutoBash: improving configuration management with operating system causality analysis

Abstract

AutoBash is a set of interactive tools that helps users and system administrators manage configurations. AutoBash leverages causal tracking support implemented within our modified Linux kernel to understand the inputs (causal dependencies) and outputs (causal effects) of configuration actions. It uses OS-level speculative execution to try possible actions, examine their effects, and roll them back when necessary. AutoBash automates many of the tedious parts of trying to fix a misconfiguration, including searching through possible solutions, testing whether a particular solution fixes a problem, and undoing changes to persistent and transient state when a solution fails. Our results show that AutoBash correctly identifies the solution to several CVS, gcc cross-compiler, and Apache configuration errors. We also show that causal analysis reduces AutoBash's search time by an average of 35% and solution verification time by an average of 70%.