You have a Compute Engine managed instance group that dynamically scales by adding and removing Compute Engine instances based on the load on your application. Each instance in this group runs a shutdown script intended to clean up by removing REDIS database entries associated with that instance when it is terminated. However, you've noticed that many of these database entries remain uncleared, suggesting that the shutdown script isn't reliably executing. To address this, you decide to use a Cloud Function to handle the removal of the database entries. What should you do next to ensure that the database clean-up is performed reliably every time an instance is shut down?