To facilitate service version management in a loosely coupled application on Compute Engine, what should you configure?

Configuring the service endpoint as metadata to be retrieved at runtime is a robust method for managing service versions in a loosely coupled application on Compute Engine. This approach takes advantage of Google Cloud's metadata service, which allows you to store and dynamically retrieve configuration data such as service endpoints or versioning information. By doing so, your application can adapt seamlessly to changes in service versions without needing to redeploy or hard code endpoints directly within the application code.

Using metadata ensures that the application components can be decoupled, providing greater flexibility. If a service endpoint changes, you can simply update the metadata rather than modifying the application code, promoting a cleaner deployment process and reducing the risk of errors. It also allows for easier scaling and management of multiple versions of services, as the application can quickly reference the correct version through the metadata.

In contrast, defining service endpoint information to be retrieved from an environment variable at runtime has its limitations, such as being less dynamic and requiring more effort to update across instances if changes occur. Creating a fixed hostname removes the flexibility needed in a versioned environment and can lead to downtime or misrouting if services change. Using label data could complicate service discovery and introduce additional overhead. Thus, leveraging metadata is the most effective approach for managing service