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redadmin1972's avatar
redadmin1972
Icon for Altocumulus rankAltocumulus
Apr 10, 2024

Pool round Robin not working with standard virtual server

I have a standard HTTPS virtual server configured with two nodes in the pool. There is no persistence setting enabled and the load balancing method is round robin. For some reason, after I browse to...
load balance
persistence
pool member
round robin
  • Paulius's avatar
    Paulius
    Apr 11, 2024

    The reason you're having this issue is most likely because of the following entry in your iRule.

     

    catch { persist uie [HTTP::header "X-Forwarded-For"] 1800 }

     

    That entry will always apply UIE persistence based on the HTTP header "X-Forwarded-For" so you then get bound to the same pool member all the time.

redadmin1972's avatar
redadmin1972
Icon for Altocumulus rankAltocumulus

Here is CLI output for the virtual server

 

From NonProd LTM:
 
ltm virtual website_https_vs {
    creation-time 2021-02-19:02:17:10
    destination 10.0.0.10:https
    ip-protocol tcp
    last-modified-time 2021-10-05:14:48:44
    mask 255.255.255.255
    pool website_https_pool
    profiles {
        website_SSL {
            context clientside
        }
        http { }
        serverssl {
            context serverside
        }
        tcp { }
    }
    rules {
        DEFAULT-IR
    }
    serverssl-use-sni disabled
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    translate-address enabled
    translate-port enabled
    vs-index 64
}

 

Here is the iRule DEFAULT-IR

when HTTP_REQUEST {
    if {not([HTTP::header exists "X-Forwarded-For"])} {
        HTTP::header insert X-Forwarded-For [IP::remote_addr]
    }
    catch { persist uie [HTTP::header "X-Forwarded-For"] 1800 }
}

 

No policies are applied

 

Standard HTTPS pool with two ephemeral nodes from FQDN lookup. Load balancing method is Round Robin and Priority Group Activation is Disabled

Paulius's avatar
Paulius
Icon for MVP rankMVP
Apr 11, 2024

The reason you're having this issue is most likely because of the following entry in your iRule.

 

catch { persist uie [HTTP::header "X-Forwarded-For"] 1800 }

 

That entry will always apply UIE persistence based on the HTTP header "X-Forwarded-For" so you then get bound to the same pool member all the time.

  • redadmin1972's avatar
    redadmin1972
    Icon for Altocumulus rankAltocumulus
    Apr 11, 2024

    I believe this iRule was identified from a previous community solution when we needed to have the X-Forwarded-For value in the packet header. I never realized the impact of this line in the iRule.

    I removed the line and tested with this iRule:

     

    when HTTP_REQUEST {
        if {not([HTTP::header exists "X-Forwarded-For"])} {
            HTTP::header insert X-Forwarded-For [IP::remote_addr]
        }
    }

     

    Now my site is load balancing with round robin properly.

     

     

    Thank you very much!