What is a backend CVM?
The backend CVM is a CVM instance that is bound to the CLB instance after the CLB instance is created and processes the corresponding forwarding requests. In the configuration CLB listener When you need to bind a CVM instance as the backend server, CLB uses different round-robin scheduling, forwarding the request to the backend CVM, which is processed by CVM to ensure the smooth and reliable operation of the application. You can bind CVM instances to one or more availability zones in the region where the CLB instance is located to increase the robustness of the application and shield single points of failure.
Notes
When adding backend servers, we recommend that you:
- Install a Web server (such as Apache or IIS) on all CVM instances to be added to the CLB, and keep running applications consistently.
- It is recommended that you enable session persistence. This feature enables the CLB to maintain a TCP connection for a longer time and reuse it for multiple requests, which can reduce the load on the Web server and improve the throughput of the CLB.
- Ensure that the security group of the backend instance has inbound rules for the CLB listener port and health check port. For details, see Access control of backend servers .