Mendix Cloud applications perform a readiness check during startup to verify the application is fully initialised and ready to serve traffic before being marked as healthy. This ensures that after operations such as a restart or deployment, traffic is only routed to the application once it can handle requests. But this readiness check has a timeout, when exceeded fails the application.

For applications with long-running startup tasks, such as database migrations that take an extended period, the readiness check can cause health check timeouts before initialization is complete. In these cases, a request to disable the readiness check for the application can be submitted via support. The readiness check is enabled by default.

Before requesting this feature, please review the following:

• Operations may report success prematurely: After a restart or deployment, health checks will report the application as healthy before it has fully started. The environment status in the Cloud Portal may show the application as running while after-startup tasks are still in progress.
• Traffic may reach an unready application: Because the application is marked as healthy immediately, it may receive user requests while still executing startup tasks. This can result in errors, timeouts, or degraded performance for end users until the application has fully initialized.
• Startup monitoring is a manual responsibility: With the readiness check disabled, there is no automated validation that the application can handle requests. Application logs should be monitored to ensure startup has completed before relying on the environment status.

Please make sure to request re-enabling the readiness check when the long-running startup tasks have been completed.