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Stefan_Klotz's avatar
Stefan_Klotz
Icon for Cumulonimbus rankCumulonimbus
May 09, 2014

External Monitor with Disable Mode

Hi there, we are using an external monitor script with a curl command including NTLM-authentication. The default HTTP WebGUI monitor just provides basic authentication method, but there you can also define a "Receive Disable String" for maintenance mode. Is this possible with an external monitor as well? Because the "echo UP" in the script has no functional meaning, means the LB doesn't care of the provided output, it just checks if there is an output. Or is such a scenario not possible at all? Thank you!

 

Ciao Stefan :)

 

application delivery
external monitor
LTM

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  • Henrik_Gyllkran's avatar
    Henrik_Gyllkran
    Icon for Nimbostratus rankNimbostratus
    May 09, 2014

    Certainly, the external monitor does whatever you tell it to do. If I had more time I could give you an example but the logic would be something like this:

     

    if the member responds with correct string - echo UP and check if member is disabled, if so issue the tmsh command to enable it.

     

    else if the member responds with the disable string - check if the member is enabled, if so issue the tmsh command to disable the member.

     

    If you're using this type of logic for multiple pools I would include the pool name as an additional parameter in the monitor configuration so you would need one monitor per pool but they can use the same script.

     

  • Stefan_Klotz's avatar
    Stefan_Klotz
    Icon for Cumulonimbus rankCumulonimbus
    May 09, 2014

    Hi Henrik,

     

    thank you for the quick answer and yes I can follow/understand your logic. But it is much easier as I found out now. Since version 11 NTLM is supported for HTTP/S monitors (search for ntlm). The only issue we had or the reason why it was not working is the domain for the username section. In the release notes there is a hint stating that

     

    the domain [...] must be capitalized for authentication to be successful.

     

    Doing this, our monitor becomes green. Hope that helps others out there as well.

     

    Ciao Stefan :)