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Embrace the Chaos: Building Reliability with Chaos Engineering

In a world where we’re becoming increasingly dependent on microservices and distributed cloud architectures, ensuring the reliability and stability of these complex systems has become a paramount concern for businesses. The last thing any company wants is a catastrophic outage preventing people to do their jobs, make their sales and damage their reputation. To avoid such nightmares, Chaos Engineering has emerged, offering a “preventative medicine” to identify failures before they escalate into major disasters. In this article, we will explore what Chaos Engineering is, how it works, what Chaos Engineering tools are available to enable teams to implement this more efficiently (e.g. through Automation), and how it can build reliability for your systems.

What is Chaos Engineering?

Chaos Engineering is a proactive methodology designed to test and analyse how a system behaves under stressful and adverse conditions. These conditions can be in the form of outages when a downstream dependency receives too much traffic or unauthorised traffic through a port that breaches security.

The core philosophy behind Chaos Engineering is that it is better to induce controlled failures in a safe environment to learn from them rather than waiting for unpredictable, real-world failures to occur.

This approach was popularised by Netflix in the early 2010s when they introduced “Chaos Monkey,” a tool that randomly terminated virtual machine instances in their production environment to test system resilience. Since then, Chaos Engineering has gained traction and has been embraced by many leading technology companies.

The Principles of Chaos Engineering

Unlike what the name may suggest, chaos engineering follows a systematic approach. The following principles describe the experimental method of chaos engineering that most adhere to:-

    • Identify a ‘Steady State’: Chaos Engineering involves gradual experimentation with controlled failures.  In order to be able to understand what the failures are, you need to define the ‘normal’ working behaviour of the system i.e. the Steady State.
    • Define a Hypothesis: Before conducting any chaos experiment, clearly define what you expect to happen. This helps in better analysis and learning from the results.
    • Ensure Minimal Disruption to Users: In chaos testing, the objective is to deliberately challenge and disrupt the system, but it is crucial to execute such tests in a manner that limits the scope of potential damage and avoids adverse effects on users. Your team bears the responsibility of directing tests towards targeted areas while being well-prepared to respond to any incidents that may arise.
    • Introduce Chaos: After ensuring your system’s stability, readiness of your team, and containment of the blast radius, you can initiate your chaos testing applications. Introduce various variables to simulate real-world scenarios, such as server crashes, malfunctioning hardware, and severed network connections. Conducting these tests in a production environment is ideal as it allows you to observe how your service or application responds to these events without directly impacting the live version and active users.
    • Monitor Continuously: During chaos experiments, it is crucial to monitor various metrics and KPIs to understand the system’s behaviour under stress accurately.
    • Learn, Automate & Improve: Chaos Engineering is not a one-time task. Continuously learning from the experiments and implementing improvements is at the core of this methodology. However, running experiments manually is labour-intensive and ultimately not achievable.  Automate experiments and run them continuously. You want to eventually disprove your hypothesis, building a robust and more reliable system.

Chaos Engineering Tools

As just mentioned, automating chaos experiments has become essential to ensure precision, scalability, and efficiency in this testing process. Let’s explore some popular chaos engineering tools and how they aid in bolstering system reliability.

Chaos Monkey:

Chaos Monkey, introduced by Netflix, was one of the first chaos engineering tools and is still used by some IT organizations. While it may be considered somewhat crude by today’s standards, Chaos Monkey’s simplicity makes it an attractive choice for some developers. The tool focuses on randomly terminating virtual machine instances to simulate unpredictable production incidents, fostering a mindset for disaster preparedness. However, one limitation is the lack of a restore or rollback mechanism, making it less suitable for larger enterprises that require well-oiled recovery strategies.

Chaos Toolkit:

The Chaos Toolkit is an open-source project that offers a collection of standard chaos experiments, supported by extensive documentation. It allows teams to create a declarative API, enabling easy programming of chaos experiments that can be version-controlled and automated by CI/CD systems. The Chaos Toolkit includes drivers for major cloud providers and other chaos engineering tools like Gremlin, providing a flexible and integrative platform for conducting experiments.

Chaos Mesh:

Another notable open-source tool, Chaos Mesh, seamlessly integrates into development workflows and Kubernetes infrastructure without requiring changes to deployment logic. This tool supports a wide range of chaos experiments and provides a user-friendly dashboard to track and manage experiments effectively. With Chaos Mesh, teams can inject bugs at various levels of Kubernetes devices, simulate latency, disrupt communications, and mimic read/write errors. It offers native integrations for major cloud platforms and helps organisations build more resilient applications.


Gremlin is a well-regarded commercial chaos engineering tool that offers numerous failure scenarios to simulate various real-world issues. From CPU attacks to network disruptions, Gremlin allows teams to identify and fix vulnerabilities and potential security problems effectively. One of its strengths is the ability to automatically detect infrastructure components and recommend relevant experiments. Gremlin’s native integrations with major cloud providers and Kubernetes, along with its ability to cancel experiments automatically in case of system instability, make it a valuable tool for organizations seeking a comprehensive chaos engineering solution.

Choosing the Right Tool:

When selecting a chaos engineering tool, teams should consider their specific needs, the complexity of their systems, and the types of failures they want to simulate. Larger enterprises with complex infrastructures may benefit from more robust and feature-rich tools like Gremlin, while smaller businesses might find simplicity and ease of use in Chaos Monkey or the Chaos Toolkit.

It’s important to note that chaos engineering is not a one-size-fits-all approach, and no tool can comprehensively test all potential real-world scenarios. Companies can augment these tools with custom experiments based on their operational risks. Furthermore, as the field of chaos engineering is still evolving, new tools and improvements are likely to emerge, providing even better options for testing and ensuring system reliability.

How Chaos Engineering Builds Reliability

    • Identifies Weaknesses: Chaos experiments expose weaknesses and vulnerabilities in a system that might go unnoticed during regular testing. By deliberately triggering failures, engineers can pinpoint potential points of failure and address them before they cause actual outages.
    • Tests Resilience with Empirical Outcomes: Chaos Engineering puts systems under realistic stress conditions. By simulating real-world scenarios, it validates whether a system can bounce back gracefully after failure. This resilience testing improves the system’s ability to recover quickly and maintain service continuity.
    • Mitigates Human Error: In many cases, human error is a significant factor contributing to system failures. Chaos Engineering helps engineers understand how their systems respond to unexpected situations and learn from these incidents to prevent human-related failures.
    • Enhances Monitoring and Alerting: Chaos experiments help in evaluating the effectiveness of existing monitoring and alerting systems. If certain failures are not adequately detected or responded to, the engineering team can improve these aspects to detect anomalies promptly.
    • Boosts Confidence: By subjecting a system to controlled chaos, engineering teams gain a deeper understanding of their system’s behaviour and limitations. This newfound knowledge instils confidence in engineers and stakeholders, knowing that their system is better prepared to handle unexpected events.


System reliability is a top priority for businesses aiming to deliver high-quality services to their customers. Chaos Engineering revolutionises reliability in today’s technology landscape by proactively testing systems through controlled failures. By identifying weaknesses and vulnerabilities, organisations can address potential points of failure before they escalate into catastrophic outages. Continuous monitoring and learning from chaos experiments enable engineering teams to improve resilience, mitigate human errors, and enhance monitoring mechanisms.

Automation tools like Chaos Monkey, Chaos Toolkit, Chaos Mesh, and Gremlin streamline the experimentation process, empowering businesses to deliver seamless services while staying ahead of potential challenges. Embracing the chaos through Chaos Engineering fosters a culture of preparedness, ensuring robust and dependable systems that can navigate the dynamic digital landscape with confidence.