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Srikanth_79730's avatar
Srikanth_79730
Icon for Nimbostratus rankNimbostratus
Mar 14, 2012

Load balancing based on load feedback from real servers

Hey Guys,

 

 

Is there a way to provide load feedback from real servers to vip ?

 

 

Assume a VIP has 3 real servers behind it.

 

Server1

 

Server2

 

Server3

 

 

Each servers exposes its load via a http url, for example

 

 

"http://Server1/load" will provide the load on Server1. Load could be a number as simple as cpu utilization percentage. (Example: 30%)

 

 

 

Now I would like the Load Balancer to periodically(say every 5 secs) poll the load on all the pool members and track it. Whenever a new request comes from client, I want to the Load Balancer to route the request to the Server which has the least load(in our case the host with least cpu utilization).

 

 

Can you please let me know if its possible to achieve this in F5 via irules or any other mechanism?

 

 

-thanks,

 

Srikanth

 

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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Mar 14, 2012
    Hi Srikanth,

     

     

    I can't think of a simple way to collect the load metrics via HTTP and dynamically modify the ratio of connections the pool members get. You could potentially use SNMP to collect load info from the server and configure dynamic ratio load balancing that way though:

     

     

    http://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm_configuration_guide_10_1/ltm_appendixb_dynamic_ratio_lb.html?sr=20084010

     

     

    Another option would be to configure a reverse HTTP monitor and disable a server when the load increases past a certain threshold so it won't receive new connections.

     

     

    Aaron