CAREER: Getting Rid of Bugs: Realizing Interactive Debugging of Networked Systems

互联网由现存最复杂的分布式软件基础设施之一组成，它由大量的系统和协议组成，这些系统和协议在大量的路由器和服务器上实现。不幸的是，这种软件的极端复杂性导致了各种各样难以隔离的故障模式和异常，将现代大型网络系统的操作变成了一个不断发现和修复问题的过程。迄今为止，对现代网络系统调试的研究主要集中在通过自动检测违反预定义正确性条件的问题来“将人从循环中移除”。然而，在实践中，网络的巨大复杂性加上对领域特定知识的基本需求来定位问题限制了现有研究的适用性，使得今天的调试成为一个艰苦的手工过程。在这项工作中，研究人员采用了一种非常不同的方法；也就是说，在网络系统中调试问题时，体力劳动是必要的，但是如果在网络中支持调试，这个过程会简单得多。在这种情况下，工作开发的技术和工具的交互式调试广域网络系统。网络软件对交互式调试提出了新的挑战，包括在面对高动态和超大规模的情况下确定事件的顺序和全局视图，使故障排除者能够交互式地理解固有的大量和潜在的不完整的观察集中存在的潜在问题，在竞争对手和对手存在的情况下定位可能破坏或限制调试器可用信息的问题。并将运行网络的性能与调试过程隔离开来。智力优势：本项目将为现代网络化系统设计第一个交互式调试系统。这项工作将对网络架构和协议设计做出重大贡献，包括：(a)允许严格控制网络执行的网络层基板，在高度分布式和动态环境中提供实时网络的再现性和性能隔离；(b)扩展，以支持在不受信任的环境中进行调试，在不需要透露私人输入的情况下对恶意行为进行本地化和诊断故障；(c)分析模型，从根本上了解现有系统可实现的诊断水平，并重新设计现有的可诊断性协议；(d)现代网络故障的特征，以及减缓调试过程或损害诊断精度的人为因素。这项工作还将产生用于网络系统交互式调试的新软件和工具，这些软件和工具将成为开源软件。更广泛的影响：网络和服务提供商今天花费数十亿美元雇用高技能的开发人员和故障排除人员。能够更有效地排除故障，减少网络停机时间，提高网络技术的可靠性和成本效益。能够在异常发生后迅速修复的网络是企业和政府通信系统在灾难中生存和恢复的重要组成部分。简化网络故障处理，也可以加快缺乏经验丰富技术人员的欠发达地区的网络部署。研究生将通过研究人员与at&t实验室的六年持续合作，以及与雅虎的持续互动，从行业互动中受益。实验室和思科研究中心。该工作关于系统和协议的哪些组件最容易产生误解，导致人为错误和调试困难的研究结果将用于减少本科网络课程中的误解。

The Internet consists of one of the most complex distributed software infrastructures in existence, made up of a vast intertwining of systems and protocols implemented over an enormous collection of routers and servers. Unfortunately, the extreme complexity of this software leads to a highly rich variety of hard-to-isolate failure modes and anomalies, turning the operation of a modern large-scale networked system into a constant process of finding and fixing problems. Research on debugging modern networked systems has thus far focused on "removing the human from the loop" by automatically detecting problems that violate predefined correctness conditions. However in practice, the enormous complexity of networks coupled with the fundamental need for domain-specific knowledge to localize problems limits the applicability of existing research, leaving debugging today a painstakingly manual process.In this work, the researchers take a very different approach; namely, the position that manual labor is a necessary evil of debugging problems in networked systems, but that this process would be vastly simpler with in-network support for debugging. In this vein, the work develops techniques and tools for interactive debugging of wide area networked systems. Networked software presents new challenges for interactive debugging, including determining an ordering and global view of events in the face of high dynamism and extremely large scale, enabling the troubleshooter to interactively understand the underlying problems present in inherently massive and potentially incomplete sets of observations, localizing problems in the presence of competitors and adversaries that may subvert or limit information available to the debugger, and isolating the operational network's performance from the debugging process.Intellectual Merit: This project will design the first interactive debugging system for modern networked systems. This work will make significant contributions to network architecture and protocol design, including: (a) a network-layer substrate that allows for tight controls on network execution, to provide reproducibility and performance isolation of the live network in highly distributed and dynamic environments; (b) extensions to support debugging in untrusted environments, to localize malicious behavior and to diagnose faults without requiring revelation of private inputs; (c) analytical models to fundamentally understand the level of diagnostics achievable in existing systems, and to redesign existing protocols for diagnosability; and (d) a characterization of faults in modern networks, and of human factors that slow the debugging process or harm diagnostic precision. This work will also produce new software and tools for interactive debugging of networked systems that will be made open-source.Broader Impact: Network and service providers today spend billions of dollars hiring armies of highly skilled developers and troubleshooters. Being able to troubleshoot more efficiently reduces network downtime, improving reliability and cost-effectiveness of networking technologies. Networks that can be rapidly repaired after exceptions are an essential component of disaster survival and recovery for business and government communication systems. Simplifying network troubleshooting can also accelerate deployment of networks in underdeveloped regions lacking experienced technicians. Graduate students will benefit from industrial interactions via the researcher's six-year ongoing collaborations with AT&T Labs, and ongoing interactions with Yahoo! Labs, and Cisco Research. The work's research results regarding which components of systems and protocols are most prone to misunderstandings, leading to human error and debugging difficulty, will be applied to reduce misunderstandings in undergraduate networking classes.