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Devlin_T_149357's avatar
Devlin_T_149357
Sep 18, 2014

Question on Topology Load Balancing

Hello all

 

I was hoping you could provide some advice. We need to do some topology load balancing on our GTMs for an application we are due to implement.

 

We have a Wide IP, let's say it's www.application.com. I intend to assign to this Wide IP two pools: Virtual-Server-DC1 and Virtual-Server-DC2.

 

What we need to happen is this:

 

  • Any user from subnet 1 must go to Virtual-Server-DC1
  • Any user from subnet 2 must go to Virtual-Server-DC2
  • All other users must be load balanced between Virtual-Server-DC1 and DC2

At the Wide IP level I will configure the load balancing method as topology. At each pool level I will configure the primary load balancing method as topology and 2nd as round robin.

 

I will then create some topology records that say:

 

  • Source IP Subnet is: subnet 1, destination pool is Virtual-Server-DC1
  • Source IP Subnet is: subnet 2, destination pool is Virtual-Server-DC2

My question(s) therefore are:

 

  1. Does this configuration look correct?
  2. Do I need to create another topology record for users that are not in subnets 1 or 2? Or will the 2nd load balancing method of round robin kick in?

Sorry if I haven't explained things clearly enough.

 

Many thanks

 

BIG-IP DNS
deployment
design

3 Replies

  • The_Bhattman's avatar
    The_Bhattman
    Icon for Nimbostratus rankNimbostratus
    Sep 20, 2014

    Hi Devlin_T,

     

    1) I think you have the right logic so it looks correct.

     

    2) if you did not define Topology record to catch everything else then it will default to the most basic behavior. Which is round robin.

     

    I hope this helps

     

  • Mahmoud_Eldeeb_'s avatar
    Mahmoud_Eldeeb_
    Icon for Cirrostratus rankCirrostratus
    Sep 21, 2014

    1: it is ok 2: you should have 3 listener (subnet-1, subnet-2, subnet-other) , each listener should forward to the specific destination like (listener-1 to destination-1, listener-2 to destination-2, listener-3 to destination-1&2).

     

  • Brian_Saunders1's avatar
    Brian_Saunders1
    Icon for Altostratus rankAltostratus
    Sep 22, 2014

    Hello Devlin,

    One other option to consider could be the following. Basically having your primary pool perform topology based load balancing and a last resort pool to handle queries that don't fall within your topology based rulesets.

    WideIP:

        gtm wideip www.application.com {
    last-resort-pool www.application.com-round_robin
    pool-lb-mode topology
    pools {
        www.application.com-topology { }
    }

    Primary Pool:

    gtm pool www.application.com-topology {
alternate-mode global-availability
load-balancing-mode topology
members {
    10.1.1.1:443 {
        order 1
        vs-name www.application.com-10.1.1.1
    }
    10.2.2.2:443 {
        vs-name www.application.com-10.2.2.2
    }
}

    Last Resort Pool:

    gtm pool www.application.com-round_robin {
members {
    10.1.1.1:443 {
        order 1
        vs-name www.application.com-10.1.1.1
    }
    10.2.2.2:443 {
        vs-name www.application.com-10.2.2.2
    }
}

    Virtual in DC1:

    gtm server LTM-DC1 {
addresses {
    10.10.10.10 { }
}
datacenter "DC1"
monitor bigip
virtual-servers {
    10.1.1.1:443 {
        name www.application.com-10.1.1.1
    }
}

    Virtual in DC2

    gtm server LTM-DC2 {
addresses {
    10.20.20.20 { }
}
datacenter "DC2"
monitor bigip
virtual-servers {
    10.2.2.2:443 {
        name www.application.com-10.2.2.2
    }
}

    Topology Rulesets:

    gtm topology  ldns: subnet 10.30.30.0/24  server: datacenter "DC1" { }
gtm topology  ldns: subnet 10.40.40.0/24  server: datacenter "DC2" { }