Forum Discussion

Chris_101737's avatar
Chris_101737
Icon for Nimbostratus rankNimbostratus
Jun 24, 2009

Standby pool Member

Hi,

 

 

New to F5, and I did a search but did not find the solution. I need to set up 2 pool members but only one member to be used at a time the second member just in standby mode only and only active when the 1st member fail.

 

 

 

Thanks
config
design
  • James_Quinby_46's avatar
    James_Quinby_46
    Historic F5 Account
    Jun 24, 2009
    Take a look in the admin/config guide at the 'priority group activation' pool setting:

     

    https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/LTM_config_guide_943/ltm_pools.html1215248

     

     

    (scroll down a bit to the section titled "Specifying priority-based member activation" and see if this is the scenario you're aiming for)
  • hoolio's avatar
    hoolio
    Icon for Cirrostratus rankCirrostratus
    Jun 24, 2009
    You could either use priority groups or a simple iRule. You can get more info on priority groups in the LTM configuration guide for your version. The iRule is here:

     

     

    Single Node Persistence

     

    http://devcentral.f5.com/wiki/default.aspx/iRules/SingleNodePersistence.html

     

     

    Aaron
  • Wales_113331's avatar
    Wales_113331
    Icon for Nimbostratus rankNimbostratus
    Feb 19, 2014

    Hi Chris,

     

    I am currently trying to implement the same scenario, could you please help out. i have 2 pool members in a VS and i need a active standby scenario for the pool members. Below is what i have pool member 1 - priority 2 pool member 2 - priority 1

     

    load balancing - round robin priority group activation - less than 1

     

    the server team are telling me traffic is still coming to both servers. do you think i am missing something here.

     

  • Christopher_Ach's avatar
    Christopher_Ach
    Icon for Nimbostratus rankNimbostratus
    Feb 19, 2014

    Yes that sounds correct. I have Round Robin selected, Less than 1 for Priority Group Activation. I have one member with Priority Group 1 and the other member in Priority Group 0

     

    Traffic only goes to Higher Priority member(s) and if in this case you loose the P1 member, traffic should go via the next lowest P group member assuming its Monitor marks it as up.

     

    Why dont you take a TCPDUMP to verify if traffic is actually going to both or just 1 pool member.

     

    Chris

     

  • bmaupin_200954's avatar
    bmaupin_200954
    Icon for Nimbostratus rankNimbostratus
    Jan 05, 2016

    Priority-based load balancing with or without dynamic persistence doesn't quite address this requirement. Priority load balancing allows you to set a preferred server to which traffic should return once it recovers. With just Priority, and with dynamic persistence of any kind enabled, when a higher priority nodes come back up after failing, you will see traffic distributed across multiple pool members until old connections/sessions die off. With just Priority and no persistence, existing sessions will break once the preferred node again becomes available.

     

    For true single node peristence, see here:

     

    https://devcentral.f5.com/codeshare/single-node-persistence