HTTP probe in ACE

axfalk · ‎07-22-2009

we have a simple layer3-4 port 80 app thta is being load balanced by ACE and created an HTTP probe that actually acts more like a TCP probe, since we took a default on just about all the attributes:

probe http WEB_SERVERS

expect status 200 200

Unfortunately, when we activated this probe, we saw the following:

probe : WEB_SERVERS

type : HTTP

state : ACTIVE

description :

----------------------------------------------

port : 80 address : 0.0.0.0 addr type : -

interval : 120 pass intvl : 300 pass count : 3

fail count: 3 recv timeout: 10

http method : GET

http url : /

conn termination : GRACEFUL

expect offset : 0 , open timeout : 10

expect regex : -

send data : -

--------------------- probe results --------------------

probe association probed-address probes failed passed health

------------------- ---------------+----------+----------+----------+-------

real : Planview_136.39[0]

167.238.136.39 1 1 0 FAILED

Socket state : CLOSED

No. Passed states : 0 No. Failed states : 1

No. Probes skipped : 0 Last status code : 302

No. Out of Sockets : 0 No. Internal error: 0

Last disconnect err : Received invalid status code

Last probe time : Wed Jul 22 15:07:20 2009

Last fail time : Wed Jul 22 15:07:21 2009

Last active time : Never

real : Planview_136.40[0]

167.238.136.40 1 1 0 FAILED

Socket state : CLOSED

No. Passed states : 0 No. Failed states : 1

No. Probes skipped : 0 Last status code : 302

No. Out of Sockets : 0 No. Internal error: 0

Last disconnect err : Received invalid status code

Last probe time : Wed Jul 22 15:07:20 2009

Last fail time : Wed Jul 22 15:07:21 2009

Last active time : Never

The obvious culprit here is the return code. How do we assign the correct return code here?

Thanks...

ciscocsoc · ‎07-22-2009

Hi,

I wouldn't just let it default. It is better to probe for a particular page if that is possible. If this is a page you create, then it offers the possibility of being able to take a server out of rotation simply by renaming the page. E.g.

probe http PROBE-iamhere

interval 30

passdetect interval 10

request method head url /serverhere.html

expect status 200 200

Alternatively, it looks like you are getting a 302 response code (a redirect) then you could just change the line in the probe to expect that.

probe http WEB_SERVERS

expect status 302 302.

HTH

Cathy

jteixido · ‎08-06-2009

I've ran into this issue with sites that require authentication or do not have a default web page configured. In a pinch and a short outage window, I've had probe TCP port 80 instead of doing a HTTP probe.

Cathy's reply may be the better route to go, since Cathy is an expert at this stuff and has answered many of my questions with her posts.

I'm going to try her method mentioned in this post the next time I run into this issue.

John...