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HUAWEI CLOUD Stack 6.5.0 Troubleshooting Guide 02

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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Health Check Exception

Health Check Exception

Symptom

A listener fails to conduct the health check.

Possible Causes

Abnormal communication with backend Cloud Servers, incorrect port configuration and health check parameters, or slow backend Cloud Server response may cause the health check exception.

Procedure

  1. Check whether a backend Cloud Server can assess applications.

    • If the backend Cloud Server can access applications, go to 2 to eliminate other faults.
    • If the backend Cloud Server cannot access applications, handle faulty backend Cloud Servers.

  2. Log in to the backend Cloud Server and verify that the backend Cloud Server port is working properly.

    Since the network between layer-7 (HTTP or HTTPS) services and the backend Cloud Server is a private network, you need to log in to the backend Cloud Server to verify that the backend Cloud Server port is working properly to ensure normal communication between the load balancer system and backend Cloud Servers.

  3. Check whether the backend Cloud Server has the port enabled.

    The port must be the same as that configured for the listener.

    For layer-4 load balancing, log in to the elb_lvs node and use telnet { Inner EIP plane}:{Backend listening port} for testing. For layer-7 load balancing, the HTTP status code must be 200 or other codes that indicate a normal status. The check methods are as follows:

    • If the backend Cloud Server runs Windows, enter the internal network address in the browser address bar of the backend Cloud Server. For example, you can enter http://{VM fip}:{backend listening port}.
    • If the backend Cloud Server runs Linux, you can run the curl -I command to check whether the status is HTTP/1.1 200 OK. For example, you can run command curl -I {VM fip}:{backend listening port}.
    • If no port is enabled, enable the port on the backend Cloud Server.

  4. Check whether the backend Cloud Server has a firewall or other security software.

    The IP address of the load balancer system is easily shielded by this type of software, causing the failure to communicate with backend Cloud Servers.

    You can disable the firewall and perform the health check again. If the backend Cloud Server status becomes normal after the firewall is disabled, the backend Cloud Server private network firewall shields the IP address of the load balancer system.

    The following commands can be used to disable the firewall:

    • Windows: firewall.cpl
    • Linux: /etc/init.d/iptables stop

    If the fault persists, continue to perform follow-up operations.

  5. Check whether health check parameters are correctly configured.

    It is recommended that you set the parameters to their default values. After the health check takes effect, check whether the fault is rectified. If the fault persists, continue to perform follow-up operations.

  6. Use a static page to perform the health check and specify the page URL in the health check configuration if the health check page you use is not the home page of the backend Cloud Server.

    It is recommended that the health check test file is a simple HTML page which is only used to display the returned result, rather than a dynamic scripting language, such as PHP.

  7. Check whether the backend Cloud Server has a heavy load, which causes the Cloud Server to respond slowly.

    • If yes, rectify the backend Cloud Server fault.
    • If no, contact technical support for assistance.

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Updated: 2019-06-01

Document ID: EDOC1100062375

Views: 1674

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