Logging doesn't work as expected

Scenario

Imagine you are working as a DevOps Engineer in a company that heavily relies on real-time data processing and logging. One day, you're notified that a critical process on one of your servers has stopped logging data. This process is essential for tracking user activities and system health. Initial observations do not show any immediate system failures, but the absence of new log entries is concerning. You need to quickly diagnose and resolve this issue to ensure continuous monitoring and data integrity.

Question

As a DevOps Engineer, you are faced with a challenge where a critical process on your system has suddenly stopped logging data. You suspect several potential issues but need a structured approach to identify and fix the problem. What do you do and where do you start?

Example solution

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Solution

1. check process config files in /proc

2. **Check disk space**: Verify available disk space and ensure it is not full. Free up space if necessary. `Du -h, Df -h , ls -arl`

3. **Review file permissions**: Check if the process has proper write permissions to the log directory. User perms? Ownership of directory has changed. `Chmod`, `Chown`. `Chgrp`

4. **Investigate log rotation**: Ensure log rotation is properly configured to prevent log files from filling up the disk. **/etc/logrotate.d/**

5. **Monitor disk I/O**: Monitor disk I/O performance to identify any issues affecting logging. **iostat, iotop**

6. **Implement centralized logging**: Adopt a centralized logging solution to streamline log management and analysis. CloudWatch Logs or Elasticsearch

7. **Enable process-level logging**: Configure the process to perform its own logging, using frameworks or libraries. mplement a logging framework (e.g., Logrus, Zap

8. **Implement fault tolerance**: Design the system with redundancy to ensure logging continuity in case of process failures. Implement redundancy by deploying multiple instances of the process, using load balancers or orchestrators, and considering backup log streams or alternate logging mechanisms