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Application Observability

Key Concepts

  • A strong observability culture is essential in order to reliably deliver new features at today’s pace.
  • It’s critical to know your user and measure what matters to them.
  • When it comes to monitoring and alerting, a relentless focus on simplicity will keep your team as effective as possible during incidents.

Outcomes

What we’ve heard from customers:

  • “We don’t want to find out about issues from our customers.”
  • “We need to reduce the cost of delivering our service.”
  • “Our monitoring often indicates that there may be an issue, but we are unsure what, if any, customer impact there may be.”

Summary

In today’s connected world, application development teams are under increasing pressure to deliver new features faster than ever before. In addition to expecting new features on a continuous basis, end-users are accustomed to high levels of reliability and will quickly look for alternative products and services if their expectations are not met.

Satisfying these ever-increasing demands is no short order. Software systems commonly consist of a multitude of microservices spanning a variety of cloud and on-premise environments, with dependencies on external services and tools. These systems require constant change in order to accommodate new features and keep up with critical security patches, but change introduces risk. A strong observability culture is essential to manage this risk and make sense of these complex systems.

The Three Pillars of Observability

When we say observability, we’re often referring to one or more of:

  • logging
  • metrics
  • tracing

Logging

It’s easy to generate logs from your applications. In fact, it’s so easy that one of the most common challenges when collecting and analyzing logs is that there is just way too much data to sift through. This is further complicated with the ephemeral nature of today’s container-based workloads that can start or stop in a matter of moments, taking the local logs with them.

In order for your logs to be of use, you need to ensure that they are collected and retained for an appropriate amount of time, easy to find, and easy to visualize. There are many ways to solve for these concerns, including logging services from cloud providers or application platforms as well as maintaining your own logging infrastructure. If you do need to stand up your own solution, there is a wide ecosystem of open-source technologies that can be used. For example, the “EFK stack” (Elasticsearch, Fluentd, and Kibana) is a popular option.

Metrics

Metrics allow you to measure the performance of your applications and infrastructure over time. In tools like Prometheus and Tanzu Observability, metrics are represented as time series with a unique name and a series of labels or tags.

Metrics often require less storage and processing resources than logs, since the resources required to collect a single time series are constant and do not scale with the utilization of the system. Additionally, since they are numerical and more structured it is easier to generate visualizations and alerts to understand the health of the system.

Tracing

Many applications today are made up of several smaller services, and communicate with a variety of external dependencies. As a result, one request from a user’s perspective may result in a series of separate requests to distinct services. Tracing is a technique that allows you to follow these related requests through the system, and is especially useful for identifying where performance problems lie.

For many teams, tracing is the most difficult aspect to implement, as all of the various components of the system need to instrumented to propagate traces. There are a number of popular open source solutions in this space, including Zipkin and Jaeger. Additionally, VMware Tanzu Observability supports any traces compatible with the OpenTelemetry framework.

Getting Started on your Observability Journey

While it can be tempting to jump straight into the world of dashboards, metrics, and alerts, we think it’s important to take a step back and focus on a few key areas as you execute on your observability strategy.

The first area of focus is identifying what to measure and how you’ll measure it. The quality of the data you collect is significantly more important than the overall quantity. The best way to reason about a system’s availability is to identify a small set of Service Level Indicators (SLIs) that closely map to the user’s experience, and set appropriate Service Level Objectives (SLOs) for each of these indicators. Getting this part right ensures that any future alerts you build will be actionable and backed by data that clearly indicates the user-facing impact.

Next, you’ll want to spend some time “refactoring” your alerting setup. Just like source code, alerting configuration has a tendency to become overly complicated and hard to understand. If your alerts are to serve you well, they need to be simple, well understood, and easy to act on. Having too many alerts can be worse than not having enough, as a team can quickly become desensitized and conditioned to ignore alerts they don’t understand or need anymore. Additionally, your observability tools should be as easy as possible for you to maintain - you don’t want to spend too much time worrying about scaling or having sufficient disk space, you want to trust that the data you need will be there for you when you need it.

Lastly, focus on building out a well-defined incident response procedure. Good alerts can help you detect issues sooner, but observability done well should provide the tooling and data needed to troubleshoot and resolve incidents. In other words, a strong observability culture can help reduce both mean time to detect (MTTD) an issue, and mean time to recover (MTTR), but only if your team knows how to effectively respond to the incident after receiving an alert. This includes everything from defining roles, responsibilities, and communications protocols to ensuring that your team is able to effectively use your tools to troubleshoot issues.