/troubleshooting-application-failures

name: troubleshooting-application-failures
description: Troubleshoots failing applications by discovering and analyzing CloudWatch log groups to identify error patterns, root causes, and actionable solutions. Use when an application is experiencing failures and log-based diagnosis is needed.
version: 2

Application Failure Troubleshooting

Overview

Domain expertise for diagnosing application failures through CloudWatch log analysis. Discovers relevant log groups, searches for error patterns and stack traces, performs root cause analysis, and generates prioritized remediation recommendations.

Logs are where the investigation starts, not its boundary. When the logs point at a timeout, throttle, retry or permission problem, read the configuration that sets it, for example the API Gateway integration timeout, the queue's visibility timeout, or the function timeout and event source mapping. Read-only access normally includes these Describe and Get calls.

Troubleshoot a failing application

To diagnose and resolve application failures using CloudWatch logs, follow the procedure exactly. See [Application failure troubleshooting procedure](references/application-failure-troubleshooting.md).

Troubleshooting

No log groups found

Ask the user for specific log group names. Common patterns: `/aws/lambda/function-name`, `/aws/apigateway/api-name`, or custom application log groups.

Access denied errors

Verify AWS credentials have `logs:DescribeLogGroups`, `logs:DescribeLogStreams`, `logs:StartQuery`, and `logs:GetQueryResults` permissions.

Query timeouts

Reduce the time window or limit results. Large log groups may require multiple smaller queries.