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

互联网由现有的最复杂的分布式软件基础设施之一组成，由在大量路由器和服务器上实现的大量交织的系统和协议组成。不幸的是，这种软件的极端复杂性导致了各种各样的难以隔离的故障模式和异常，将现代大规模网络系统的操作变成了一个不断发现和修复问题的过程。 调试现代网络系统的研究，迄今为止集中在“消除人类的循环”，自动检测的问题，违反了预定义的正确性条件。 然而，在实践中，网络的巨大复杂性，加上对特定领域知识的基本需求，以本地化问题，限制了现有研究的适用性，使调试今天一个艰苦的手工过程。也就是说，在网络系统中，手工劳动是调试问题的必要之恶，但是这个过程在网络内支持调试的情况下会简单得多。 在这种情况下，工作开发的广域网络系统的交互式调试技术和工具。 网络化软件为交互式调试提出了新的挑战，包括在面对高动态性和极大规模时确定事件的顺序和全局视图，使调试器能够交互式地理解存在于固有的大量和潜在不完整的观察集合中的潜在问题，在存在可能破坏或限制调试器可用信息的竞争者和对手的情况下定位问题，智能化优点：本项目将为现代网络系统设计第一个交互式调试系统。 这项工作将对网络体系结构和协议设计做出重大贡献，包括：（a）允许对网络执行进行严格控制的网络层基底，以在高度分布式和动态环境中提供实时网络的可再现性和性能隔离;（B）支持在不可信环境中调试的扩展，（c）分析模型，以便从根本上了解现有系统可达到的诊断水平，并重新设计现有的可诊断协议;以及（d）现代网络中的故障的表征，以及减缓调试过程或损害诊断精度的人为因素的表征。 这项工作还将产生新的软件和工具，用于网络系统的交互式调试，这些软件和工具将成为开源的。更广泛的影响：今天的网络和服务提供商花费数十亿美元雇佣大量高技能的开发人员和调试人员。 能够更有效地进行故障排除可减少网络停机时间，提高网络技术的可靠性和成本效益。 在发生异常后能够迅速修复的网络是企业和政府通信系统灾难生存和恢复的重要组成部分。简化网络故障排除还可以加快缺乏经验丰富的技术人员的欠发达地区的网络部署。研究生将受益于工业互动，通过研究人员的六年持续合作与AT T实验室，并与雅虎正在进行的互动！实验室和思科研究中心。这项工作的研究结果，关于系统和协议的组成部分是最容易产生误解，导致人为错误和调试困难，将应用于减少误解，在本科网络类。

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.