Zebrium Blog

Kubernetes makes it easy to deploy, manage and scale large distributed applications. But what happens when something goes wrong with an app? And how do you even know? We hear variations on this all the time: “It was only when customers started complaining that we realized our service had degraded”, “A simple authentication problem stopped customers logging. It took six hours to resolve.”, and so on.

A widely prevalent application monitoring strategy today is sometimes described as “black box” monitoring. Black box monitoring focuses just on externally visible symptoms, including those that approximate the user experience. Black box monitoring is a good way to know when things are broken.

Kubernetes and other orchestration tools use abstraction to hide complexity. Deploying, managing and scaling a distributed application are made easy. But what happens when something goes wrong? And, when it does, do you even know?

It is especially tricky to identify software problems in the kinds of distributed applications typically deployed in k8s environments. There’s usually a mix of home grown, 3^rd party and OSS components – taking more effort to normalize, parse and filter log and metric data into a manageable state. In a more traditional world tailing or grepping logs might have worked to track down problems, but that doesn’t work in a Kubernetes app with a multitude of ephemeral containers. You need to centralize logs, but that comes with its own problems. The sheer volume can bog down the text indexes of traditional logging tools. Centralization also adds confusion by breaking up connected events (such as multi-line stack traces) in interleaved outputs from multiple sources.

A quick, free and easy way to find anomalies in your logs

Why understand log structure at all?

Observability means being able to infer the internal state of your system through knowledge of external outputs. For all but the simplest applications, it’s widely accepted that software observability requires a combination of metrics, traces and events (e.g. logs). As to the last one, a growing chorus of voices strongly advocates for structuring log events upfront. Why? Well, to pick a few reasons - without structure you find yourself dealing with the pain of unwieldy text indexes, fragile and hard to maintain regexes, and reactive searches. You’re also impaired in your ability to understand patterns like multi-line events (e.g. stack traces), or to correlate events with metrics (e.g. by transaction ID).

At Zebrium, we have a saying: “Structure First”. We talk a lot about structuring because it allows us to do amazing things with log data. But most people don’t know what we mean when we say the word “structure”, or why it allows for amazing things like anomaly detection. This is a gentle and intuitive introduction to “structure” as we mean it.