Skip to content

Application Query Library

Use these CloudWatch Logs Insights queries against application stdout and stderr logs to isolate startup failures, uncaught exceptions, and recurring error signatures in Elastic Beanstalk application processes.

When to Use

  • Use when an environment turns Severe or Degraded immediately after deployment and you suspect application startup crashes.
  • Use when recurring exceptions appear in health cause messages and you need the full stack trace and frequency.
  • Use during triage to distinguish between platform-level failures and application-level bugs.
  • Use after code changes to verify that no new exception patterns have been introduced.

Prerequisites

  • CloudWatch Logs agent enabled on the Elastic Beanstalk environment (aws:elasticbeanstalk:cloudwatch:logs namespace).
  • Application stdout log group streaming to CloudWatch: /aws/elasticbeanstalk/$ENV_NAME/var/log/web.stdout.log.
  • IAM permissions for logs:StartQuery, logs:GetQueryResults, and logs:FilterLogEvents.
  • Familiarity with your application's logging format and exception output patterns.

Log Group Pattern

/aws/elasticbeanstalk/$ENV_NAME/var/log/web.stdout.log

Replace $ENV_NAME with your environment name. Some platforms also emit to var/log/eb-engine.log for platform-level application lifecycle events.

flowchart LR
    A[Application stdout / stderr] --> B[CloudWatch Logs Agent]
    B --> C[CloudWatch Log Group]
    C --> D[Application Query Library]
    D --> E[Startup Errors]
    D --> F[Runtime Exceptions]

Interpretation Guidance

  • Startup errors within seconds of deployment indicate missing dependencies, configuration errors, or port binding failures. Cross-reference with the Deployment Events platform query to confirm timing.
  • Recurring runtime exceptions with increasing frequency suggest a progressive failure such as connection pool exhaustion or memory leak. Check the Instance Degraded Health playbook.
  • Exceptions only on specific instances may indicate instance-level issues rather than application bugs. Compare per-instance logs and check CPU and Memory Exhaustion.

Queries

Query Description Link
Startup Errors Find boot-time crashes, bind failures, and dependency initialization errors startup-errors.md
Runtime Exceptions Count recurring exceptions and stack-trace prefixes during normal traffic runtime-exceptions.md

See Also

Sources

  • https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/AWSHowTo.cloudwatchlogs.html
  • https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/CWL_QuerySyntax.html
  • https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/AnalyzingLogData.html