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santosh_81454's avatar
santosh_81454
Icon for Nimbostratus rankNimbostratus
Apr 27, 2011

health monitor issues.

Hi,

 

 

We are currently load balancing our app servers using the F5 boxes running v10.2.0.We tried using multiple health monitors but they failed / ineffective due to the following reasons. the app servers are running on ATG/Jboss. Please let me know if anyone faced this issue earlier and resolved it.

 

 

 

Http - Creating n number of sessions. The session created for the health monitor check do not terminate.

 

tcp - works fine under less traffic. But when performing load test or high traffic, the box flips the nodes active/inactive within seconds causing error in the site.

 

External Health monitor - We are using SNMP and this is causing the CPU to be very high. Currently we just enabled the health monitor for one brand and its running at 79% avg. cpu. (We have five more brands to go)

 

inband monitor - is not effective as it marks the node active even when the node is disabled.

 

management
monitoring
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Apr 28, 2011
    Hi Santosh,

     

     

    Can you make a single (or less ideally, multiple) HTTP request(s) which either do not generate a session or generate a session and then expire it? If so, you could try to mimic that in an HTTP health monitor. If it requires multiple requests, you could build a script and external monitor which references the script.

     

     

    Aaron
  • santosh_81454's avatar
    santosh_81454
    Icon for Nimbostratus rankNimbostratus
    Apr 29, 2011
    Hi Aaron,

     

     

    Yes, we are also looking in that direction of creating just single http request. Is it possible in F5 to use a cookie or some header to, such that we re-use the same session for health monitoring instead of creating new sessions everytime ?

     

     

     

    Thanks,

     

    Santosh.

     

  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Apr 29, 2011
    Hi Santosh,

     

     

    With an inbuilt monitor you cannot save something from one monitor response and reuse it for a later request. This type of functionality is only available via an external monitor which calls a shell script. Here is a template you could use for an external monitor:

     

     

    http://devcentral.f5.com/wiki/default.aspx/AdvDesignConfig/TemplateForExternalLtmMonitors.html

     

     

    You'd need to modify this to save the output from one request and reuse it.

     

     

    Aaron