Mastering Observability in Kubernetes Production Environments: Part II — Logging

Outlined in Part I of our Observability in Kubernetes Production Environments series, we focused on the first cornerstone of observability: monitoring. Monitoring Kubernetes lays the groundwork for efficient system monitoring and error detection.

In Part II, we will explore the basics of Kubernetes logging, including the various components you can log, the different types of logs you can collect, and the numerous solutions available for managing and analyzing these logs.

Whether you're a seasoned Kubernetes user or a newbie, this guide will provide the knowledge you need to implement effective logging for your Kubernetes applications in production.

The importance of logging

Logs comprise a comprehensive record of events, errors, and informational messages generated by applications and their systems. Understanding the importance of logging in production environments is crucial for maintaining efficient operations and security. This includes a range of considerations, such as:

  • Debugging and troubleshooting issues: Logs are vital for tracing events that resulted in problems, making resolution quicker and more efficient.
  • Security and compliance: Logs offer evidence of unauthorized access attempts or suspicious activity; they also help meet regulatory requirements, potentially avoiding penalties for non-compliance.
  • Analyzing application behavior: Logs provide insights into application behavior under various conditions, supporting performance optimization, user experience improvement, and data-driven decision-making.

Kubernetes is an open-source system designed to automate the deployment, scaling, and management of applications within containers. This system has rapidly emerged as the prevailing standard for orchestrating containerized workloads. The scale at which Kubernetes operates, often managing hundreds or thousands of containers, highlights the importance of efficient logging practices.

In Kubernetes, logs both provide this visibility into the state and behavior of individual containers and offer a holistic view of the cluster's health and performance. As applications become more distributed and dynamic, effective logging becomes crucial for identifying issues that may span multiple containers and nodes. Thus, a well-implemented logging strategy is essential to successful Kubernetes deployments.

Logging basics in Kubernetes

Understanding the log sources in Kubernetes is the first step toward effective logging. Each component of your Kubernetes setup — from your applications running inside the pods to the system services on each node to the API server handling requests — generates valuable logs. These logs can illuminate different aspects of your system's behavior, performance, and security.

Application Logs

These are generated by your applications running inside Kubernetes pods. They are the primary source of insight into how your application behaves in a live production environment. Application logs can help you troubleshoot issues specific to your application's functionality or performance.

Infrastructure Logs

System logs in a Kubernetes context refer to logs from each node's system services, such as the kubelet, the container runtime (e.g., Docker), and the node operating system itself. These logs help identify and debug issues related to the Kubernetes system and infrastructure, which might indirectly affect your applications.

Kubernetes API Logs and Audit Events

Kubernetes audit logs record all the requests made to the Kubernetes API server, who made each request, when it was made, and the response. These logs can be of critical importance for understanding user activity and system changes; they are particularly valuable for maintaining security and compliance.

In the next part of this series, we will discuss how to manage and analyze these logs.

Kubectl: A built-in logging solution for Kubernetes

Given the complexity and scale of logging in a Kubernetes environment, it's clear that a robust, scalable logging solution is essential. Kubernetes provides kubectl, a built-in tool to fetch and view logs.

Kubectl is a command-line interface that lets you fetch and view logs directly from your terminal. You can retrieve a specific pod or container’s logs using the kubectl logs command. However, this tool has limitations if you require large-scale, production-grade logging, as it doesn't provide log storage, analysis, or alerting capabilities.

Best practices for Logging in high-scale production environments

The following actions can help maintain effective and efficient logging when dealing with extensive, production-grade environments.

Log rotation and retention policies

Implement log rotation to prevent individual log files from becoming too large, which can impact system performance. Additionally, define log retention policies that automatically delete old log data to conserve storage space.

Log filtering and enrichment

Not all log data is valuable. Implement log filtering to exclude irrelevant log entries and reduce the volume of log data. Logs can also be enriched with additional context, like Kubernetes metadata, to make them more informative.

Centralized logging architecture

Implement a centralized logging architecture that collects logs from all applications and components into a single, central location. This makes searching and analyzing log data easier across your entire system.

Logging aids in security as much as debugging and troubleshooting

Although often overlooked, logging is an indispensable aspect of managing and maintaining any robust application, especially in a Kubernetes environment. The right logging practices not only aid in debugging and troubleshooting but also play a significant role in ensuring security, maintaining compliance, and analyzing application behavior.

Part III of this Kubernetes series will focus on another critical observability practice: tracing. Stay tuned to continue your journey on the road to making the most of your Kubernetes production environments.

Continue to Part III: Kubernetes tracing in production >