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heskez_36146's avatar
heskez_36146
Icon for Nimbostratus rankNimbostratus
Sep 10, 2013

Problems with http health monitor

Hi,

 

We've created an health monitor to receive a string "1000" which is found on the web page we're trying to monitor.

 

Our webserver is IBM Wepshere

 

The string SEND part is: GET /index.html HTTP/1.1\r\nHost: ourhost.domain.com:9080\r\nConnection: Close\r\n

 

Receive string is: 1000

 

Somehow the pool member give status down when this monitor is applied. While our webserver shows the correct page. We've seen in our firewall logs traffic at port 9080 is accepted by the webserver.

 

What else could we have been overlooking.

 

availability
design
health monitor
ibm
microsoft

10 Replies

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  • JG's avatar
    JG
    Icon for Cumulonimbus rankCumulonimbus
    Sep 10, 2013

    You need an extra pair of "\r\n" after "Close".

     

  • heskez_36146's avatar
    heskez_36146
    Icon for Nimbostratus rankNimbostratus
    Sep 10, 2013

    Hi, thanks for replying. The syntax should be like this? GET /index.html HTTP/1.1\r\nHost: ourhost.domain.com:9080\r\nConnection: Close\r\n\r\n

     

    • JG's avatar
      JG
      Icon for Cumulonimbus rankCumulonimbus
      Sep 10, 2013
      Yes. And actually, remove ":9080" from Host.
    • Hem_66900's avatar
      Hem_66900
      Icon for Cirrus rankCirrus
      Sep 11, 2013
      Below link would help in understanding setting up Carriage Return (CR) & Line Feed (LF) http://support.f5.com/kb/en-us/solutions/public/2000/100/sol2167.html?sr=31828166
  • Kevin_Stewart's avatar
    Kevin_Stewart
    Icon for Employee rankEmployee
    Sep 10, 2013

    The two carriage returns, as part of the RFC specification, indicates to the server the separation between methods/headers and any payload. There's no payload, so it indicates the end of the request. Previous versions of LTM automatically inserted these carriage returns. Newer versions do not.

     

  • heskez_36146's avatar
    heskez_36146
    Icon for Nimbostratus rankNimbostratus
    Sep 25, 2013

    Thanks for all support and explanation. So now we'd like to improve our health monitoring. At this point the health monitor points towards a floating ipaddress. We'd like to cut this part out and the rule should be like this:

     

    GET /index.html HTTP/1.1\r\nUser-Agent: F5 BIG-IP Monitor\r\nConnection: Close\r\n\r\n

     

    However this syntax seems to be incorrect because all members are put offline immediately.

     

  • JG's avatar
    JG
    Icon for Cumulonimbus rankCumulonimbus
    Sep 25, 2013

    Try this:

    GET / HTTP/1.0\r\nUser-Agent: F5 BIG-IP Monitor\r\n\r\n