keepalive problem

Unanswered Question
Apr 9th, 2007
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hi guys,

please i have configured this keepalive and service as shown:


keepalive Server-1

type http

port 81

method get

uri "/HealthCheck2/HealthPageTest/Default.aspx"

ip address 10.0.207.71

active


service Server-1

ip address 10.0.207.71

port 81

keepalive method get

keepalive type named PreBancs1Keepalive

active



after configuring the keepalive the server become Alive (which is very good)

After some times (maybee 3 hours or less) the service become Down and when i make suspend and active to the keepalive it become Alive again ???


any idea pleass, urgent

Hasan Odeh

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hassan_oudeh Mon, 04/09/2007 - 06:55
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sorry i made a mistake while pastin the config


keepalive Server-1

type http

port 81

method get

uri "/HealthCheck2/HealthPageTest/Default.aspx"

ip address 10.0.207.71

active


service Server-1

ip address 10.0.207.71

port 81

keepalive method get

keepalive type named Server-1

active



Syed Iftekhar Ahmed Mon, 04/09/2007 - 11:02
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hassan~


Could you try using "keepalive method head" instead of "keep alive method get"?


With Get method CSS computes an MD5 (Message Digest Algorithm Version 5)hash value on the page, and stores the hash value as a reference hash. Subsequent GETs require a 200 OK status and the "hash value to equal the reference hash value". If the 200 OK status is not returned, or if the 200 OK status is returned but the hash value is different from the reference hash value, the CSS considers the service down.


If the URI you are monitoring changes by only a bit then CSS will consider it down.


Hope it helps

Syed Iftekhar Ahmed

hassan_oudeh Mon, 04/09/2007 - 11:17
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Dear Syed,


the customer is looking for GET for the keepalive,

But even if the hash value is not matched and the CSS consider it Down, by the next check it should came up again, but its not.

Am I right ?

i mean why after suspen and active it came back.


what i found also from the show keepalive during the service Down there is KeepAlive Error

Any idea ?


Thanks,

Hasan Mohammad Odeh


Syed Iftekhar Ahmed Mon, 04/09/2007 - 11:31
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Suspending and then activating the service forces the CSS to recalculate the hash.

As long as the page remains the same CSS will mark them alive.As soon as there is a change, the new hash value will differ the earlier calculated value and CSS will mark the Server down.


In a nutshell

If the pages are dynamic you cant use the get method with CSS.


Syed Iftekhar Ahmed

hassan_oudeh Mon, 04/09/2007 - 11:44
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yes Syed, i got your point


and yes the page is dynamic,

on the server they are doing some internal testing (for SQL and AD standalone servers) and they put the result into that page as true or false (true=200 false=something else) and CSS is checking that page.


So as i understan its a MUST to be HEAD ?

Syed Iftekhar Ahmed Mon, 04/09/2007 - 13:25
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Yes...With dynamic page you cannot use Get.


Syed Iftekhar Ahmed

Gilles Dufour Tue, 04/10/2007 - 04:19
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if you really need a GET, you can use a scripted keepalive. There a few of them available by default that you can use directly or rewrite to fit your need.


ie:


ap-kal-httplist 3 APR 07:25:14 1674

ap-kal-httptag 3 APR 07:25:14 1180


Gilles.

thumpercisco Wed, 05/09/2007 - 11:32
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If you have to authenticate prior to getting to this uri would this config still work or what would be the work around for requiring an authentication

hassan_oudeh Wed, 05/09/2007 - 12:14
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Thanks thumpercisco, i cant play around the authentication because the everything is in production now :) but i didn't configure any http authentication.


i think it was a problem of get method, because i changed the method to head and i didn't face that problem anymore.

this is because as Efthikhar said i have a dynamic page for healthchek

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