Docker service unhealthy or application responds 500

Prerequisites and authority

Start with read-only checks and authorized records. Capture evidence before changes. Stop and escalate when data replacement, financial changes or wider outages are possible.

Service unhealthy or application returns 500

Basic

Determine which surfaces fail and whether the error began after an update/configuration change. Preserve one visible error and the incident time.

Intermediate

Run docker ps -a, inspect Compose status using Docker Compose, volumes and service lifecycle, and check the API health route. A container being Up differs from passing its health check. Check MySQL before restarting the API repeatedly.

Advanced

Read bounded logs for the affected service and dependency. Check storage, environment presence, image/version compatibility and migrations. Avoid displaying resolved secrets through broad configuration dumps.

Correct the named dependency or restart the smallest wedged service after evidence capture. Do not perform a broad teardown or remove volumes. If an update caused the failure, follow the supported rollback procedure.

Verify the original action, login, worker progress and database connectivity. A 200 response from one health endpoint does not prove every workflow recovered. Escalate recurring exceptions with the exact service version and error window.