Before you use an Edge Load Balancer (ELB) instance, you need to add a backend server to receive client requests.
Prerequisites
An ELB instance is created. For more information, see Create an ELB instance.
An Edge Node Service (ENS) instance is created as the backend server to receive client requests. For more information, see Create and manage instances.
Limits
You can add ENS instances to or remove ENS instances from an ELB instance anytime. ELB distributes network traffic across groups of ENS instances.
You need to enable the health check feature in ELB and make sure that at least one ENS instance works as expected.
ELB does not support cross-node deployment. The ENS instances that you add to an ELB instance and the ELB instance must be on the same node.
To simplify management and maintenance, we recommend that an ELB instance and ENS instances that you add to the ELB instance use the same operating system.
You can configure a default server group in ELB.
Usage notes
You can specify a weight for each ENS instance in a server group. An ENS instance with a higher weight receives more requests.
If ELB and session persistence are enabled at the same time, requests may not be evenly distributed across backend servers. We recommend that you disable session persistence.
Each listener serves a backend application.
ELB uses listening ports to receive client requests and forward the requests to backend ports that are used by the applications on ENS instances.
Procedure
Log on to the ENS console.
On the ELB Instance page, find the instance that you want to manage, and click Add Backend Server in the Actions column.
On the Default Server Group tab, click Add.
On the My Servers page, select the ENS instance that you want to add and click Next.
On the Configure Weight page, specify the weight of each ENS instance.
NoteAn ENS instance with a higher weight receives more requests.
Click Add.