Instrumentation is a critical component of monitoring application performance within the DevOps framework, enabling teams to detect errors, ensure predictability in release cycles, and enhance user experience through actionable insights. It involves the use of Application Performance Management (APM) tools, daemons, and log management to provide comprehensive views of an application's state and health. Key to successful instrumentation is understanding what to measure and how it aligns with both technical and business processes, as outlined by James Fryman at Monitorama 2016. Fryman emphasizes the importance of following a structured approach, akin to a DevOps version of Maslow's hierarchy of needs, starting with a culture of learning and experimentation. Despite potential pushback, particularly due to past unproductive attempts, iteration and developer collaboration are crucial for refining instrumentation practices. Additionally, the text highlights the use of Java agents and daemons like StatsD for data collection, and the role of log management tools in streamlining the analysis of extensive log data to improve application reliability.