• Elastic Load Balancing

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  5. How Do I Rectify a Health Check Failure?

How Do I Rectify a Health Check Failure?

ELB initiates a heartbeat check on backend servers, and the load balancer communicates with backend servers over an intranet. To achieve a successful health check, you must ensure that your servers are routable from the intranet. You can perform the following steps to rectify a health check failure.

  1. Check whether the load balancer is a classic or enhanced load balancer. If it is a classic load balancer, go to 2. If it is an enhanced load balancer, go to 3.
  2. In the Listeners area, locate the listener for which the health check fails, and click View in the Health Check column. The Health Check dialog box is displayed.
    • Health Check Protocol/Port: Ensure that the protocol has been configured and port has been enabled for the server to be checked.
    • Check Path: If HTTP is used for the health check, check whether the health check path for the server is correct.
  3. Click the name of the target load balancer. Click Backend Server Groups and then click the name of the target backend server group. In the Basic Information area, click Configure on the right of Health Check.
    • Protocol and Port: Ensure that the protocol has been configured and port has been enabled for the server to be checked.
    • Check Path: If HTTP is used for the health check, check whether the health check path for the server is correct.
  4. Ensure that software, such as the firewall, in the server, does not block the health check source IP addresses.
  5. Check whether the rules of backend server security groups and network ACL allow access by 100.125.0.0/16, and configure the protocol and port used for health check. View the health check protocol and port from the health check configuration dialog box.
    • If the health check protocol is not specified, the service port of the backend server will be used.
    • If the specified health check port is different from that of the backend server, both the health check port and service port must be permitted.
  6. If the health check failure persists, contact customer service.