Before you use the Classic Load Balancer (CLB) service, you must add at least one backend server to the default server group to receive client requests.

Prerequisites

Before you add an Elastic Compute Service (ECS) instance to the default server group, make sure that the following requirements are met:
  • A CLB instance is created. For more information, see Create a CLB instance.
  • ECS instances are created and applications are deployed on the ECS instances to receive requests.

Procedure

  1. Log on to the CLB console.
  2. On the Instances page, select the region where the CLB instance that you want to manage is deployed.
  3. On the Instances page, click the ID of the CLB instance. On the Default Server Group tab, click Add.
  4. In the My Servers panel, select one or more ECS instances and click Next on the Select Servers wizard page.
  5. On the Ports/Weights wizard page, specify the weight of each ECS instance and click Add.
    An ECS instance with a higher weight receives more requests.
    You can change the weight of a backend server and then move the pointer over Batch operation to apply the change to other backend servers.
    • If you click Replicate to Below, the weights of all backend servers below the current server are set to the weight of the current server.
    • If you click Replicate to Above, the weights of all backend servers above the current server are set to the weight of the current server.
    • If you click Replicate to All, the weights of all backend servers in the default server group are set to the weight of the current server.
    • If you click Reset after you clear the weight of the current server, the weights of all other servers in the default server group are also cleared.
    Notice
    • Valid values of weights: 0 to 100. If you set the weight of a backend server to 0, the server does not receive requests.
    • If two backend servers have the same weight, requests are distributed to both servers.
  6. In the Servers to Add panel, confirm the backend servers and click OK.