Docker healthchecks only check process response, not real app health

Docker's HEALTHCHECK instruction runs a periodic command inside a container and marks it healthy or unhealthy based solely on the exit code returned. The mechanism does not read response bodies, interpret JSON, or verify whether dependencies like databases or queues are actually functioning. A common pattern — a curl call to an endpoint that returns a static 200 OK — only confirms the process is accepting TCP connections, not that business logic is working. This gap becomes costly when teams treat a green 'healthy' status as a full signal of application health, reducing attention to logs and richer metrics. Developers bear full responsibility for implementing endpoints that genuinely probe critical dependencies if they want the healthcheck to reflect real application state.