topic Hash cookie predictor with ACE Cookie insert in Application Networking

Hash cookie predictor with ACE Cookie insert

Yahshanulla S — Wed, 17 Aug 2011 02:19:19 GMT

Hi,

We have implemented the config with ACE Cookie Persistance and in serverfarm we used hash cookie <ACE Cookie>. We see equal load balanincg when we do load genrator test.

But will it create any other issue and is this advisable?

Config:

serverfarm host SF-S1WBCT-WLS-S11916

predictor hash cookie ACE-COOKIE-EVEREST-STG

rserver RS-S1WBCT-WLS-10.102.161.251-S 11916

probe PR-S1WBCT-WLS-S11916

inservice

rserver RS-S1WBCT-WLS-10.102.162.11-S 11916

probe PR-S1WBCT-WLS-S11916

inservice

rserver RS-S1WBCT-WLS-10.102.162.12-S 11916

probe PR-S1WBCT-WLS-S11916

inservice

rserver RS-S1WBCT-WLS-10.102.162.13-S 11916

probe PR-S1WBCT-WLS-S11916

inservice

rserver RS-S1WBCT-WLS-10.102.162.14-S 11916

probe PR-S1WBCT-WLS-S11916

inservice

rserver RS-S1WBCT-WLS-10.102.162.15-S 11916

probe PR-S1WBCT-WLS-S11916

inservice

sticky http-cookie ACE-COOKIE-EVEREST-STG SG-S1WBCT-WLS-S11916

cookie insert browser-expire

timeout 15

replicate sticky

serverfarm SF-S1WBCT-WLS-S11916

policy-map type loadbalance first-match LB-S1WBCT-WLS-S11916

class class-default

sticky-serverfarm SG-S1WBCT-WLS-S11916

policy-map multi-match GP-SUBPROD-01-VIP

class VC-S1WBCT-WLS-S11916

loadbalance vip inservice

loadbalance policy LB-S1WBCT-WLS-S11916

loadbalance vip icmp-reply active

nat dynamic 150 vlan 202

connection advanced-options TCP_PARAM_MAP

appl-parameter http advanced-options http_parameter_map

Hash cookie predictor with ACE Cookie insert

ohynderi — Wed, 17 Aug 2011 08:50:59 GMT

Hi,

Why do you need hash predictor with cookie insertion?

The predictor algorithm will only be used in case an http request doesn't have the ACE-COOKIE-EVEREST-STG cookie. So the predictor won't find any data to hash…

--Olivier

Hash cookie predictor with ACE Cookie insert

Yahshanulla S — Wed, 17 Aug 2011 11:32:40 GMT

Thanks for reply.

You are correct. First HTTP request will not have any ACE Cookie , so i assume it will go to new available server. isnt it? The reason we used is, With this predictor only we are seeing Equal load balancing with 6 servers. Other Predictors Least Conns, Round Robin giving Unqual Load balancing and some of the users never been used.

So Please advise How Hash Cookie Predictor works here and how its giving good equal load balancing?

Re: Hash cookie predictor with ACE Cookie insert

ohynderi — Wed, 17 Aug 2011 14:13:48 GMT

If an http request doesn't contain the expected cookie, ACE should do round robin. In that case, the server weight won't be taken into account.

You should try the following:

1/ configured round robin with cookie insertion

2/ clear the stats (clear serverfarm )

3/ genereat x requests

4/ check the serverfarm stats

5/ same steps with leastconn and hash predictor

Small q, does your traffic generator actually learn cookies?

Olivier

Hash cookie predictor with ACE Cookie insert

Yahshanulla S — Wed, 17 Aug 2011 16:21:13 GMT

SO even if we have HASH COOKIE predictor in this case ACE will do round robin when it see no cookie in header right? Nothing will get dropp of from ACE i hope.

We tried with round robin and cookie insertion, Least connection and hash predictor. Only Hash predictor gives good load balancing results.

I will ask Load ganarators about cookie clear option. Do you see any difficulties of having HASH COOKIE predictor

Hash cookie predictor with ACE Cookie insert

parveesm123 — Thu, 18 Aug 2011 03:09:36 GMT

Hi,

Even I used the same way ( pedictor as hash cookie and stickiness based on http cookie insertion)

for me too load balancing works perfectly fine.

now i am also amazed to see the reply....

So in this way , predictor is never invoked ?... in that case how is it equally load balancing ...

thanks,

Parvees

Re: Hash cookie predictor with ACE Cookie insert

ohynderi — Thu, 18 Aug 2011 12:17:11 GMT

Your understanding is correct, in case a request doesn't contain the cookie name configured in the predictor, request won't be dropped. The round robin algorithm will be used instead.

The fact the hash cookie give better result that round robin is quite strange to me. I would recommend you to confirm this and open a TAC SR if this turns out to be indeed the case.

Parvees, with cookie insertion, the predictor is used to load balance requests that don't have the cookie. If a request contain the cookie, it is simply forwarded according to the sticky db.

--Olivier