sample_runbook.md

exception: "Stale database connection"
tags: stale_db, stale_db_connection, connection_pooling
mitigation:
- Runbook Owner: [Your Name]
- Last Updated: [Date]

Steps to Mitigate:

1. **Identify Affected Instances:**
   - Monitor application logs, database logs, and performance metrics to identify instances experiencing stale database connections.

2. **Confirm the Issue:**
   - Check for other symptoms like slow query performance or connection errors to confirm that stale database connections are the cause.

3. **Runbook Execution:**
   - Execute the following steps to address the issue:

   - **Step 1: Run Lambda1:**
     - Run a Lambda function that monitors and identifies instances with stale database connections. This Lambda should trigger alerts or notifications.

   - **Step 2: Run Lambda2:**
     - Run a Lambda function that clears or resets the connection pool for the affected instances. This will help release any stale connections.

   - **Step 3: Validate:**
     - After running Lambda1 and Lambda2, monitor the application's behavior and performance metrics to ensure that the issue has been resolved.

4. **Automate Remediation:**
   - Consider automating the above steps using AWS CloudWatch Alarms, Amazon CloudWatch Events, and AWS Lambda. This can provide proactive detection and automatic remediation.

5. **Preventive Measures:**
   - Implement the following preventive measures to minimize the recurrence of stale database connection issues:

   - Optimize Connection Pooling:
     - Configure connection pool settings appropriately to manage the lifecycle of connections and prevent staleness.

   - Health Checks:
     - Implement regular health checks for database connections to identify and handle stale connections proactively.

   - Application Logging and Monitoring:
     - Implement robust logging and monitoring to quickly identify and respond to any emerging connection issues.

   - Load Testing:
     - Conduct load testing scenarios to identify how the application behaves under different loads and ensure connection pool settings are adequate.

6. **Documentation and Communication:**
   - Update this runbook with any lessons learned or additional steps discovered during mitigation.

7. **Escalation:**
   - If the issue persists or escalates, involve the appropriate teams, such as AWS Support or database administrators, for further assistance.

8. **Post-Mitigation Analysis:**
   - After resolving the issue, analyze the root cause and incorporate the findings into your application's best practices.

Remember to customize the runbook with specific details relevant to your environment and application. Additionally, keep the runbook up-to-date and share it with your team for reference during future incidents.