Debugging Essentials: A Comprehensive Approach to Resolving Critical System Issues-PART 1

Swift debugging in critical systems is crucial to prevent revenue loss and protect reputation. Prompt issue resolution minimizes downtime, ensuring uninterrupted operations and customer satisfaction. It demonstrates commitment to reliability and competitiveness in the digital landscape.

Have you ever experienced critical incidents like system outages, performance degradation, security breaches, infrastructure failures, service disruptions, or received severe customer complaints?

These incidents may manifest as HTTP errors such as 500 or 403, spikes in monitoring tools, or escalations from your operations team. Your team enters panic mode, gathering in a war room to tackle the issue. Amidst the chaos, one person suggests checking Redis, another mentions investigating recent releases, and someone else shares their New Relic or Kibana screen while another team member opens up RDS monitoring.

However, amidst the confusion, someone realizes that the team is lacking direction. This person steps forward, suggesting that responsibilities be divided and identifying some common reasons for these errors. They present a plan to quickly resolve the issue and stabilize the system. The team appreciates this individual’s contribution and leadership.

In this tech blog, we will explore various cases that can help you debug effectively in such challenging situations.

Case: Unexpected spike in HTTP Error 500(Internal server error)

1. Examine error logs: This step is crucial and straightforward. Begin by analyzing the error logs to identify the specific piece of code generating the error. Pay attention to any error messages that can provide valuable insights and guide you towards the next steps of debugging. Determine whether the issue stems from infrastructure problems or code-related issues.
2. Validate infrastructure status: Verify the operational status of all infrastructure components. Confirm that essential services are functioning properly and running without any issues. Keep a close eye on system resource utilization, including CPU, memory, and disk space, db connections to detect any potential bottlenecks or failures. It is often helpful to analyze to the error logs to pinpoint the specific component that may have encountered a failure.
   
   If you encounter a connection problem with a particular infrastructure component, the initial course of action is to attempt a restart of that component, provided you have the necessary access and permissions. Alternatively, triggering a new deployment can automatically establish fresh connections.
   If the issue persists despite these attempts, it is advisable to promptly involve the DevOps or SRE (Site Reliability Engineering) team. Their expertise can be instrumental in diagnosing and resolving complex infrastructure-related issues.
3. Addressing code issues: If a sudden 500 error arises from a specific line of code and it is determined to not be an infrastructure problem, it is highly likely that the error stems from a recent release. In such cases, it is recommended to investigate the recent release and, if feasible, consider reverting it to a stable state.
   Instead of spending valuable time identifying the root cause of the issue, prioritize stabilizing the system swiftly with minimal effort. The immediate objective should be to identify and apply a patch or workaround to resolve the error promptly, without delving into discussions about the ideal coding approach.
4. Investigate recent configurations: Check for any recently enabled configurations or settings that could impact the system’s behaviour.
   Revert the config immediately if possible.
5. Examine inputs and file uploads: Verify if incorrect or unexpected inputs were provided. Investigate if the code section in question is being processed by a background job that takes user input dynamically, also consider Consider the possibility of erroneous file uploads by the operations team, which may be causing the issue.
6. Verify external services: Pay close attention to any unexpected errors originating from external services. It’s important to recognize that errors from external dependencies can manifest as 500 errors within your application, connection issues, or even changes in the expected response format.
7. Testing and Staging Environments: If available, compare the behavior of the application in the production environment to that of testing or staging environments. This can help identify differences in configuration, infrastructure, or data that might be contributing to the errors.
8. Collaboration and Communication: Engage proactively with your team, including developers, system administrators, and other stakeholders involved in the debugging process. Encourage open communication channels to gather insights, share observations, and coordinate efforts.
   One effective practice is to assign a teammate the responsibility of actively communicating the status of the issue. This team member should regularly update relevant stakeholders with timely information and provide a tentative timeline for issue resolution. By keeping stakeholders informed, anxiety and panic can be minimized, fostering a more productive and focused environment for troubleshooting and resolving the problem at hand.

These are some of the steps that you can focus on to quickly get the issue resolved, remember:

Divide responsibilities: Assign specific tasks and areas of investigation to team members, ensuring clear ownership and efficient utilization of resources.

Focus on system stability: Prioritize stabilizing the entire system as the main objective, even if it involves implementing temporary fixes or workarounds rather than pursuing optimal solutions.

Consider patching: Be open to releasing patchy code or applying temporary fixes that can quickly address the immediate issue and restore system functionality.

In the upcoming sections, we will delve into the following cases:

• RDS: Sudden spike in CPU, memory, and DB connections.
• 403 Errors: Unexpected increase in 403 responses.
• System Load: Sudden increase in system load.

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