Smart Access Gateway (SAG) supports health check. You can create health check instances to test the network connectivity. Health check ensures that workloads can be automatically switched between different network connections. This topic describes how to create a health check instance in the SAG console.

Prerequisites

Health check is enabled. Health check is available to selected users only. To request the permission to use this feature, submit a ticket.

Background information

Health check tests the network connectivity between the source and destination IP addresses based on the routes associated with the health check instance. This feature ensures that workloads can be automatically switched between different network connections. After you create a health check instance, you must associate the health check instance with routes that point to the target destination CIDR block, and set the route advertisement policy. The SAG instance advertises and withdraws routes based on the result of health check and specified advertisement policy. This ensures that your workloads can be automatically switched between active and standby networks connections. For more information about associating routes with health check, see Configure health check.

Procedure

  1. Log on to the SAG console.
  2. Click the ID of the target SAG instance.
  3. On the instance details page that appears, click the Health Check tab.
  4. Click Create Health Check.
    Creat HC
  5. In the Create Health Check dialog box that appears, set the required parameters.
    Config HC
    Parameter Description
    Instance Name Specify a name for the health check instance.

    The name must be 2 to 100 characters in length and can contain digits, underscores (_), periods (.), and hyphens (-). It must start with a letter or Chinese character.

    Description Enter a description for the health check instance.

    The description must be 2 to 256 characters in length and can contain digits, underscores (_), periods (.), and hyphens (-). It must start with a letter or Chinese character.

    Health Check Type Select the type of packet used in heath checks. Currently, only ICMP_ECHO is supported.
    Destination IP Enter the destination IP address in health checks.

    If you need to test the network connectivity of a leased line, select the Virtual Border Router check box and then select the target virtual border router (VBR) from the Destination IP drop-down list.

    Note The destination IP address must be accessible through the routes used by SAG.
    Source IP Enter the source IP address in health checks.

    If you need to test the network connectivity of a leased line, enter an IP address in the CIDR block from which workloads are routed to the private network through the leased line.

    Note If you need to test the connectivity to different destination IP addresses, specify a unique source IP address for each destination IP address. Make sure that the source and destination IP addresses are accessible from both directions.
    Detection Interval Enter the health check interval. The next health check does not start only after the current one is complete. Valid values: 1000 to 60000. Default value: 2000. Unit: milliseconds.
    Note The interval must be longer than the timeout period of health checks.
    Detection Times Enter the number of packets to be transmitted during each health check. Valid values: 1 to 20. Default value: 1.
    Health Check Timeout Period Enter the timeout period of each health check. Valid values: 10 to 30000. Default value: 1000. Unit: milliseconds.
    Maximum Detection Failures Allowed Enter the number of consecutive health check failures that will trigger an alert. Valid values: 1 to 15. Default value: 3.
    Maximum RTT Allowed Enter the maximum round-trip time (RTT) allowed. Value values: -1 and 1 to 5000. Default value: -1, which indicates that no RTT threshold is set. Unit: milliseconds.
    Maximum Number of Times RTT Threshold Can be Exceeded Enter the maximum number of times that the RTT threshold is exceeded before an alert is triggered. Valid values: 1 to 15. Default value: 3.
  6. Click OK.