Per-Virtual Service Custom Health Check Settings

In LoadMaster firmware version 7.2.52, the check Interval, Timeout, and Retry Count settings can be configured on each Virtual Service. Previously, these were just global settings. You can configure the global settings in Rules & Checking > Check Parameters. The global settings are used by default for all Virtual Services.

To configure these settings for a specific Virtual Service, expand the Real Servers section of the Virtual Service or SubVS modify screen. A Real Server Check Method must be selected to see the relevant fields. You can configure these settings to either use the global value, set a specific value within the provided range, or reset to the default value.

If you configure these settings for a parent Virtual Service and then create a SubVS within that Virtual Service, the check values are reset to use the global values.

Interval(sec)

Specify the number of seconds that will pass between consecutive checks.

Recommended and default value: 9 seconds

Valid values range from the <mininterval> (9) to the <maxinterval> (901).

The <mininterval> is Retry Count * Timeout (sec) + 1, that is, a maximum value of 9 by default.

The <maxinterval> is 901 [because that is what 60 (maximum Timeout (sec)) * 15 (maximum Retry Count) + 1 is].

In the User Interface (UI), if the value of Check Interval is over 120 (because it is forced to this value by setting the Timeout (sec) and Retry Count), it cannot be changed by modifying the Interval(sec) drop-down list. To change it, configure the other two options. Otherwise, the maximum value that the interval can be set to is 120.

Timeout (sec)

The HTTP request has two steps: contact the server, and then retrieve the file. A timeout can be specified for each step; how long to wait for a connection, how long to wait for a response.

Default value:4 seconds

Valid values range from 4 to 60.

Retry Count

This specifies the number of retry attempts the check will make before it determines that the server is not functioning.

Default value: 2

Valid values range from 2 to 15.

For further details on health checking in general, refer to the Long Term Support (LTS) Health Checking Feature Description document.

Application Programming Interface (API) Details

You can set the chkinterval, chktimeout, and chkretrycount values when running an addvs or modvs RESTful API command. For example:

/access/modvs?vs=<VirtualServiceIPAddress>&port=<Port>&prot=<tcp/udp>&chkinterval=20

For further details on the RESTful API in general, refer to the LTS RESTful API Interface Description document.

For PowerShell help, run the Get-Help command for the relevant commands.

Command Line Interface (CLI) Details

The following parameters can also be configured using the CLI:

  • chkinterval
  • chktimeout
  • chkretrycount

If any of these parameters are set to 0 they inherit the global value.

For further details on the CLI in general, refer to the LoadMaster CLI Interface Description.

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