Steps and considerations for configuring backend servers-Edge Node Service(ENS)-阿里云帮助中心

To use the load balancing service, add backend servers to receive requests forwarded by the listeners of an Edge Load Balancer (ELB) instance.

Prerequisites

You have created an ELB instance. For more information, see Create an ELB instance.
You have created backend servers (ENS instances) to receive forwarded requests. For more information, see Create an instance.

You can add or remove backend ENS instances for an ELB instance at any time. You can also adjust traffic distribution across different ENS instances.

Enable the health check feature and make sure the ELB instance has at least one healthy ENS instance.
Load balancing does not support cross-node deployment. Make sure the ENS instance and the ELB instance are on the same node.
For easier management and maintenance, use ENS instances that run the same operating system.
ELB supports configuring a default server group.

You can specify a weight for each ENS instance in the backend server pool. ENS instances with higher weights receive more requests.
If both load balancing and session persistence are enabled, requests may not be distributed evenly across backend servers. If traffic distribution becomes uneven, disable session persistence temporarily.
Each listener maps to one application on a backend ENS instance.
The listener port maps to the application port on the backend ENS instance.

Log in to the ENS console.
On the ELB Instance management page, find the target instance, and then click Add Backend Server in the Actions column.
On the Default Server Group tab, click Add.
On the My Server page, select the target ENS instance and click Next.
On the Configure Weight page, specify a weight for the added ENS instance.

Note
An ENS instance with a higher weight receives more requests.

In the Configure Weight step, enter a weight for each backend server in the Weight column, and then click Add.
Click Add.