Your team has just launched a new feature, and everything appears to be running smoothly. But as user traffic ramps up, the application suddenly crashes. After investigating, you discover that it was killed due to excessive resource consumption—either running out of memory or exceeding its allocated CPU limits. The application’s demand unexpectedly spiked beyond what was anticipated, leading to repeated failures as more users attempted to access the service.

Mitigating the Impact

The quickest way to get your application back online is to allocate additional resources. If the crash was caused by an out-of-memory error, increasing the memory limit in your deployment configuration and restarting the application may resolve the issue.

If your system supports auto-scaling, you can spin up additional instances and configure them to start in a staggered manner. This prevents a sudden flood of new instances consuming excessive resources at once, helping maintain stability.

However, simply adding more resources may not be a long-term fix. It’s important to investigate whether the spike was caused by a memory leak, inefficient processing, or unexpected workload patterns, which may require optimizing your code or configuration.

Understanding the Pattern & Preventing Future Incidents

This failure pattern occurs when an application exceeds its allocated or available resources, resulting in crashes or degraded performance. Common causes include:

• Misconfigured resource limits, where the application is given too little CPU or memory.
• Unexpected traffic spikes, leading to higher-than-anticipated resource consumption.
• Inefficient processing or memory leaks, gradually consuming resources until the application fails.

The immediate solution involves scaling up the resources allocated to the application. This could mean increasing memory, CPU, or adding additional instances in a cloud environment. Ensuring that the new instances are started in a staggered manner can prevent a sudden surge in resource consumption that might overwhelm the system again. Over the long term, it’s crucial to monitor resource usage patterns and adjust configurations to avoid such incidents, possibly incorporating alerts for when resource usage approaches critical thresholds.

Load and performance testing, using tools like k6 or other frameworks, can provide valuable insights into how your application stack behaves under stress. Running these tests regularly helps identify and anticipate bottlenecks across all components, allowing you to address potential issues before they lead to critical failures.

Stay Tuned!

In the next post of this series, we will explore what happens when credentials or certificates expire, what immediate steps to take, and how to prevent such issues in the future.

More Info & Contact

You want to ensure your application stays stable during unexpected spikes in traffic? We’re here to help – contact us at hello@qualityminds.de or call +49 911 660732011!

This post is part of a larger series about typical outage patterns and how to short term mitigate them while on-call. Please visit Foreword: Navigating the Storms of Software Outages | QualityMinds to find all other posts.