Written by Marcos Teixeira and Reviewed by Felipe Almeida
When it comes to modern software systems, people often use “monitoring” and “observability” interchangeably. But they’re actually two different ways to understand and manage complex systems. While monitoring is more related to the process of collecting and analyzing data and establishing predefined metrics and alerts to deal with urgent issues, observability is more like a system characteristic: a system is observable when it provides comprehensive and real-time insights into its internal state, performance, and interactions, enabling effective troubleshooting, debugging, and proactive identification of issues.
Understanding the differences between monitoring and observability is crucial for effectively managing modern software systems and troubleshooting issues that may arise. We’ll explore what each term means, their respective benefits and limitations, and how they can be applied in different real-life scenarios. By the end of this post, you should clearly understand when to use monitoring or observability to gain visibility into your systems.
Key Differences Between Monitoring and Observability: Definitions and Concepts
Monitoring
Monitoring focuses on collecting and analyzing predefined metrics to gain insights into system health and performance. It involves tracking key indicators such as CPU usage, memory consumption, network latency, and error rates. Monitoring systems typically employ predefined thresholds and alert mechanisms to notify stakeholders when specific metrics exceed acceptable limits. The emphasis lies on maintaining the system’s stability and identifying deviations from expected behavior.
Imagine a machine learning model that is deployed in a production environment to make predictions on incoming data. Through monitoring, you can track various metrics such as model accuracy, prediction latency, and data drift. When the model accuracy drops below a certain threshold or the prediction latency increases significantly, monitoring tools can trigger alerts, allowing proactive measures to address the issue. Monitoring helps identify anomalies and provides a basic understanding of model health but may fall short when it comes to diagnosing complex issues.Monitoring is an essential tool for detecting when systems are over or under predictable thresholds that someone has previously deemed an anomaly.
However, modern systems are so complex that they can produce behaviors that no one can predict beforehand. This unpredictability often leads to situations where the system operates within acceptable limits, but something still seems off. In such cases, monitoring alone may not be sufficient to diagnose the issue. This is where observability comes in handy.
Observability
Observability goes beyond traditional monitoring by offering a deeper understanding of system behavior, even without pre-set metrics. It helps answer “why” something happened by providing context and detailed data. Observability includes monitoring and logging but also adds distributed tracing, real-time analytics, and event correlation. This allows engineers to better understand a system, track interactions between parts, and find the root causes of issues.
The migration from monoliths to microservices has further emphasized the need for observability beyond metric-based monitoring tools. In a microservices architecture, systems are composed of numerous interconnected services that work together to deliver functionality. This complexity makes it difficult to identify issues that may arise and pinpoint their root causes. Observability provides engineers with deep insights into how the system behaves, enabling them to trace requests across different services and diagnose complex issues. Without observability, it can be challenging to understand the interactions between components, leading to increased downtime and slower time-to-resolution.
Let’s say you have a system made up of many interconnected services. Observability tools can track and link request flows, letting you follow a specific user request across various services and find any issues or failures. With observability, you get access to logs, metrics, and traces that give a complete view of the system’s behavior. This clearer view makes troubleshooting, debugging, and performance optimization more effective.
“Monitoring is for the known-unknowns, but observability is for the unknown-unknowns” – Observability Engineering, 2022
Key Differences Summarized:
| Monitoring | Observability | |
| Focus | Emphasizes predefined metrics and thresholds | Focuses on understanding system behavior and answering “why” questions |
| Proactive vs. Reactive | Enables proactive alerting based on predefined thresholds | Enables reactive troubleshooting by providing deep insights into system behavior |
| Contextual Understanding | Often lacks a comprehensive contextual understanding of system behavior and internals | Provides contextual information and a comprehensive view of the system’s internals, enabling root cause analysis, performance optimization, and debugging |
| Scalability | Well-suited for simpler systems with predefined metrics | Performs well in complex, distributed architectures where understanding the interdependencies is crucial |
Observability is an interesting approach because it enables engineers to understand how the system behaves under normal conditions and to detect issues before they become critical. With this powerful tool, engineers can quickly diagnose and resolve issues, and make data-driven decisions about how to improve the system’s performance and reliability.
Another important difference between observability and monitoring is the level of detail. Monitoring typically provides high-level metrics and alerts, while observability provides detailed insights into the system’s behavior. With observability, engineers can drill down into specific requests, transactions, or components to understand how they are performing and identify areas for improvement.
Use Cases and Practical Applications: When to Choose Monitoring or Observability
When considering the choice between monitoring and observability, it’s important to carefully evaluate the specific requirements of your system. Here are some examples and practical applications to help you figure it out:
| Use Monitoring when | Description |
| You have a simple system with predefined metrics | Such as monitoring the accuracy of a sentiment analysis model on customer reviews. For example, you can track the model’s precision, recall, and F1 score to ensure it meets the desired performance thresholds |
| You need to track specific health indicators to ensure stability | Like tracking key models health indicators such as accuracy, precision, and latency. Monitoring these metrics helps identify performance fluctuations and data inconsistencies, allowing proactive measures for stable and reliable models |
| You want to receive proactive alerts when metrics exceed acceptable limits | For instance, in an anomaly detection system, you can set up monitoring to continuously monitor the anomaly score of incoming data. If the score surpasses a predefined threshold, an alert can be triggered, notifying the relevant stakeholders about potential anomalies in the data |
| You need to quickly identify deviations from expected behavior | For example, By comparing current feature distributions with historical baselines, you can identify any significant deviations. This allows you to promptly recognize shifts in data patterns or unexpected changes in feature behavior |
| Use Observability when | Description |
| You have a complex, distributed system with numerous interconnected services | Consider a machine learning platform that consists of multiple microservices responsible for data preprocessing, model training, and prediction serving. In this scenario, observability can be used to monitor and analyze the interactions between these services, including request flows, dependencies, and performance metrics. By implementing observability practices, you can gain visibility into the entire system’s behavior and identify any bottlenecks or issues that may arise within the distributed architecture |
| You need deep insights into the system’s behavior, even in the absence of predefined metrics | Suppose you have developed a recommendation engine for an online streaming platform. Observability provides insights into recommendation generation, even without predefined metrics. Techniques like distributed tracing and logging trace user request through components, offering a comprehensive understanding of the system’s recommendation process |
| You want to trace user requests across different services and pinpoint bottlenecks or failures in real-time | For instance, when deploying a recommendation system, observability allows you to track user requests as they traverse through various components like data preprocessing, model serving, and result generation. By adopting observability, you can quickly pinpoint any performance issues or failures in the system, ensuring seamless user experience and efficient model deployment |
| You need contextual information and rich data sets to understand “why” something happened | Imagine a data pipeline responsible for processing and transforming large volumes of customer data. Let’s say a data quality issue arises where certain customer records are being inaccurately transformed. With observability in place, you can trace the data flow through the pipeline, identify the specific transformation step or component that caused the issue, and investigate the contextual information and rich data sets available at that point |
Conclusion
Monitoring and observability are both important for managing complex systems. While monitoring is useful for tracking predefined metrics and receiving proactive alerts, observability provides deeper insights into system behavior. Understanding the differences between these two approaches can help you choose the right one for your system.