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Ilian_Ivanov's avatar
Ilian_Ivanov
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Jul 10, 2017

Choose pool based on HTTP Response

Is there any way to select a pool based on HTTP response?

 

For example: the default pool is responding on different URIs with different redirects. I don`t want the client to see that redirect, instead F5 to choose a different pool based on the redirect sent by the default pool. Is that possible?

 

3 Replies

  • Hi Ilian,

     

    I don't think it is possible to do it transparently to the client. Because the selection of the pool/pool member can be done in two manner using commands :

     

    1) "pool" - link https://devcentral.f5.com/wiki/irules.pool.ashx

     

    2) "LB::reselect" - link https://devcentral.f5.com/wiki/irules.lb__reselect.ashx

     

    Both commands are not valid for HTTP_Response event.

     

    The "HTTP::retry" command is interesting but you can not choose another pool (or pool member).

     

  • Hi,

     

    Can you explain what do you expect.

     

    The pool is already selected when the server responds. ;-)

     

  • I was able to do this by collecting all the headers on each request in HTTP_REQUEST combined with a select pool based on using a flag set in HTTP_RESPONSE, then if a retry was required, set the flag true and calling HTTP::retry with the headers caused the HTTP_REQUEST to select the new pool.

     

    Unfortunately I cannot paste the code but it did work on 11.5 and above.