In Ray Serve, you can use an object store like Redis to store objects and state information for your deployed services, but it's not strictly necessary. The use of an object store depends on your specific use case and requirements. Here's some information to help you understand when you might use an object store in Ray Serve:
1. **Object Store Purpose**: The Ray object store (e.g., Redis) is used to store stateful objects and data that are shared across different replicas of a deployed service. It allows you to maintain state for your services, making them suitable for applications that require managing session data, maintaining state, or sharing information between replicas.
2. **Stateful Services**: If your Ray Serve services are stateful and need to remember information across requests or invocations, then using an object store like Redis can be beneficial. For example, if you're deploying a chat application, you might use Redis to store chat room data and maintain state across chat service replicas.
3. **Stateless Services**: If your services are stateless and don't require shared state information, you may not need to use an object store. Stateless services can operate independently, and you can focus on scaling and load balancing without the need for shared state management.
4. **Scale and High Availability**: If you plan to scale your services across multiple replicas or have high availability requirements, an object store can be helpful. It ensures that stateful information is synchronized and shared correctly among replicas.
5. **Complex Use Cases**: In more complex use cases where you need to maintain shared state, manage configuration information, or perform distributed coordination, an object store can simplify the implementation.
In summary, using an object store like Redis in Ray Serve is not always necessary, but it can be valuable for stateful and complex use cases. If your services are stateless and don't require shared state, you can use Ray Serve without an object store. However, for services that need to maintain state or share data, the object store becomes a crucial component for synchronization and coordination.