Imbalance LB in "Select different persistence methods"

Question

Hi F5 Expert,&nbsp;
Could you help me check this error in the following, or give me a template of iRules about this requirement?&nbsp;
Thanks in advance.&nbsp;
Requirement:
Separate app request from www request about persistence. 
www request ---&gt; cookie persistence
app request ---&gt; source_addr persistence.&nbsp;
I try to edit iRules, but has issue, Error is "TCL error: /Common/MY.Test.iRules.201505013  - Prerequisite operation not in progress (line 1) invoked from within "HTTP::host”"&nbsp;
Because F5 technical guy had configured my current F5 per this requirement before, but it caused imbalance LB, seems current iRules doesn't work, all of traffic went to fallback(source_addr persistence).(default persistence is cookie, fallback is source_addr).
It's really hard for me to solve it, could you give me any feedback, please ?&nbsp;
Hope you can answer me ASAP. thanks.&nbsp;
Best Regards,
Susie.&nbsp;

nitass · Answer

Because F5 technical guy had configured my current F5 per this requirement before, but it caused imbalance LB, seems current iRules doesn't work, all of traffic went to fallback(source_addr persistence).(default persistence is cookie, fallback is source_addr).

can you post the irule? and why do you think it does not work?

susie_su_201256 · Answer

Hi,

iRules:
when HTTP_REQUEST {
     If we are using the App, we should override the default persistence profile
     We will force the use of a hash for client_ip and x-forwarded-for
    if { [string tolower [HTTP::host]] eq "app.xyz.com" } {
        log local0. "Bypassing Cookie Persistence: [string tolower [HTTP::host]][string tolower [HTTP::path]]"

If there is an X-Forwarded-For header, use this
        if {[HTTP::header X-Forwarded-For] != ""}{
            log local0. "Using X-Forwarded-For: [HTTP::header value "X-Forwarded-For"]"
            persist uie [HTTP::header X-Forwarded-For] 600

Otherwise, use Client IP Address
        } else {
            log local0. "Using IP: [IP::client_addr]"
            persist uie [IP::client_addr] 600
        }
    }
}

Because current result of LB, It's pretty imbalance, and based /Statitics/Local Traffic/Persistence Records, I found www page generated named source address affinity record.

susie_su_201256 · Answer

It's enough, or need me offer much more information ?&nbsp;

nitass · Answer

Because current result of LB, It's pretty imbalance, and based /Statitics/Local Traffic/Persistence Records&nbsp;

which one is imbalance? is it web or application?&nbsp;
if it is application, do you know if all requests contain x-forwarded-for header?&nbsp;

I found www page generated named source address affinity record.&nbsp;

i understand fallback persistence record is always created (it does not mean it is being used).&nbsp;

nitass_89166 · Answer

Because current result of LB, It's pretty imbalance, and based /Statitics/Local Traffic/Persistence Records&nbsp;

which one is imbalance? is it web or application?&nbsp;
if it is application, do you know if all requests contain x-forwarded-for header?&nbsp;

I found www page generated named source address affinity record.&nbsp;

i understand fallback persistence record is always created (it does not mean it is being used).&nbsp;

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Imbalance LB in "Select different persistence methods"

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