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Ping-based health check

Last Updated: Jun 16, 2021

What is the ping-based health check feature?

The ping-based health check feature is provided by Global Traffic Manager (GTM) to verify the addresses of an application service. On the Address Pool Configurations page, you can configure a ping-based health check to monitor each IP address in the address pool and obtain the status of each IP address. If an error occurs on an IP address, the IP address is automatically blocked. If the IP address becomes available, it is automatically unblocked.

Parameters

1. Check Protocol

The protocol type of the health check. Set the value to ping. Then, you can monitor the network accessibility, packet loss rate, and latency of the IP address.

2. Check Interval

The interval at which ping-based health checks are performed. Default value: 1 minute. If you use GTM Ultimate Edition, you can set this parameter to a minimum value of 15 seconds.

3. Number of Ping Packets

The total number of ping packets that are sent to the address for each check. This parameter is used to calculate the packet loss rate. Valid values: 20, 50, and 100.

4. Packet Loss Rate

The packet loss rate for each check. The packet loss rate in a check = The number of lost packets/The total number of ping packets × 100%. If the packet loss rate reaches the threshold, an alert is triggered. Valid values: 10%, 30%, 50%, 80%, 90%, and 100%.

5. Timeout Period

The timeout period of responses to ping packets. If a ping packet does not generate a response within a specified period, a timeout occurs. Valid values: 2, 3, 5, and 10 seconds.

6. Number of Consecutive Failures

The number of consecutive failures. If the health check feature detects the specified number of consecutive failures, GTM determines that the application service is abnormal. This prevents the impact of network jitter and ensures monitoring accuracy. Valid values: 1, 2, and 3.

  • The value 1 indicates that GTM determines that the application service is abnormal if 1 failure is detected.

  • The value 2 indicates that GTM determines that the application service is abnormal if 2 consecutive failures are detected.

  • The value 3 indicates that GTM determines that the application service is abnormal if 3 consecutive failures are detected.

Notice

Check address if there is network failure, icmp destination unreachable, such cases are not counted in the failure rate, so no alarm is generated. Please fix the address network problem in time, or replace it with HTTP health check task.

7. Failure Ratio

The ratio of abnormal monitoring nodes to the total number of monitoring nodes. If the failure ratio exceeds the specified threshold, GTM determines that the application service is abnormal. Valid values: 20%, 50%, 80%, and 100%.

8. Monitoring Node

The geographical location where the monitoring node resides. Monitoring nodes are available in the following regions:

Notice

If the address pool addresses are all Ali cloud addresses, and use the black hole policy for failure testing, please select non-BGP nodes for monitoring nodes. (Reason: Black hole is an ACL policy that takes effect in the Internet of Ali cloud network and carrier network, but the traffic between Ali cloud IP is basically flowing inside the cloud network, reducing the detection effect.)

Node type

Location

Border Gateway Protocol (BGP) nodes

China (Zhangjiakou), China (Qingdao), China (Hangzhou), China (Shanghai), China (Hohhot), China (Shenzhen), and China (Beijing)

Nodes outside mainland China

China (Hong Kong), Germany (Frankfurt), Singapore (Singapore), US (California), Australia (Sydney), Malaysia (Kuala Lumpur), and Japan (Tokyo)

Carrier nodes

China Unicom in Wuhan, China Unicom in Dalian, China Unicom in Nanjing, China Unicom in Tianjin, China Telecom in Qingdao, China Telecom in Changsha, China Telecom in Xi'an, China Telecom in Zhengzhou, China Mobile in Shenzhen, China Mobile in Dalian, China Mobile in Nanjing

Procedure

1 . Log on to the Alibaba Cloud DNS console.

2 . In the left-side navigation pane, click Global Traffic Manager. Then, click the ID of the instance that you want to manage.

  • If the GTM instance is not configured, you must configure the instance. For more information, see Tutorial overview and Enable health check.

  • If the instance is configured, click the Address Pool Configurations tab. On this tab, turn on the Health Check switch, and then click Modify. You can modify parameters based on the feature description.

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