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TechT's avatar
TechT
Icon for Nimbostratus rankNimbostratus
Apr 01, 2015

Active F5 device

We know we can configure LTM to be in Active/Standby or Active/Active mode.

 

My questions are : 1 ) Anyone knows how LTM determine the Unit is going to be Active of its own when we connected to the network, what are the factors involved into it ? Is there any priority set for the UNIT by default ? 2) What are the processes, which can happen to the system when we do a Force Standy to make the Unit standby ?

 

Let me know if you are confused, i can try rephrasing with some examples again

 

-Maneesh

 

active
application delivery
LTM

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  • Hannes_Rapp's avatar
    Hannes_Rapp
    Icon for Nimbostratus rankNimbostratus
    Apr 01, 2015

    Are you using F5 BigIP v11.x platform (not Viprion) ?

     

    1. The device with the highest management IP address will be selected as the active device by default, unless the peering unit is explicitly configured in forced offline state.
    2. If you force your active unit to standby mode, it will retain it's standby status, until next system failure of the active unit. This behavior can be changed by enabling failback configuration - not recommended.

    While you are doing any activities which will break the active-standby cluster, I recommend issuing the forced offline status on your standby unit. Alternatively, just disable all network interfaces besides the mgmt interface. You'll know you can't screw things up this way :).

     

  • TechT's avatar
    TechT
    Icon for Nimbostratus rankNimbostratus
    Apr 01, 2015

    Hannes, Thanks for your response, YES i am using v11.x

     

    Still i didnt get complete answer to my question, you said it will prefer the highest management IP of the Unit(thanks for this answer for my first question). So when we do a force standby on primary unit what is the parameter which device check/use to make the Unit standby ?

     

  • DevBabu_174449's avatar
    DevBabu_174449
    Icon for Cirrus rankCirrus
    Apr 01, 2015
    root@(ltm1)(cfg-sync Standalone)(Active)(/Common)(tmos) list sys db failover.state
sys db failover.state {
    value "active"
}
  • Hannes_Rapp's avatar
    Hannes_Rapp
    Icon for Nimbostratus rankNimbostratus
    Apr 07, 2015
    As far as I'm aware, at very core, the DB record value for 'failover.state' determines if unit is active or standby. To check the current value, issue 'tmsh list sys db failover.state' command. It's either "active" or "standby". I believe this value gets overwritten by the BigIP software, whether you forcefully set the unit to standby, or in case a system failure occurs.