Catching Timeout and HTTP 502/503 Errors

I would do something like the following:

 

when RULE_INIT {

 

set static::sorryPage {insert desired HTML here}

 

}

 

 

when HTTP_RESPONSE {

 

if { [HTTP::status] == 502 or [HTTP::status] =503 } {

 

clientside { HTTP::respond $static::sorryPage }

 

}

 

}

Hi GavinW,

 

 

The TCP Profile does not care about the availability of the "Content" being served by an application. It only checks to see that there is a "Service" listening on that port and responding. So as long as apache is alive and well the BigIP will keep sending traffic to it even if the application is in flames.

 

 

I would suggest an HTTP or HTTPS Health Check. You can set them to dig as deeply into the site as you wish to verify the availability of your application.

 

 

The F5 can either do a redirect or even provide a custom response itself when it sees an HTTP Status code that you tell it to look for. You can get more information on the HTTP::status command in the HTTP_RESPONSE event here:

 

 

http://devcentral.f5.com/wiki/iRules.HTTP__status.ashx

 

 

Hope this helps.

Michael/Patrick

 

 

That looks perfect for catching the 502/503 errors...

 

 

However how would I go about catching a long running session that time's out?

 

 

Cheers

 

Gav

 

Basically the same way. Just find out what HTTP::status code it is throwing and handle it the same way. The HTTP::status handler can capture any status code: 200, 301, 302, 500, etc.

 

 

I would advise caution in handling too much though and suggest sticking with the status codes that report on hard failures or explicit behaviors (300's or 500's). The 200's and 400's are part of normal application behavior.

If you want to handle slow server responses, you could tune the TCP profile settings for triggering the LB_FAILED event:

 

 

LB_FAILED iRule event

 

http://devcentral.f5.com/wiki/iRules.lb_failed.ashx

 

 

sol7559: Overview of the TCP profile

 

http://support.f5.com/kb/en-us/solutions/public/7000/500/sol7559.html

 

 

Or you could use the after command in an iRule to set a timer in HTTP_REQUEST_SEND. The second example should give you a good start:

 

 

http://devcentral.f5.com/wiki/iRules.after.ashx

 

 

Aaron

If you want to handle slow server responses, you could tune the TCP profile settings for triggering the LB_FAILED event:

 

 

LB_FAILED iRule event

 

http://devcentral.f5.com/wiki/iRules.lb_failed.ashx

 

 

sol7559: Overview of the TCP profile

 

http://support.f5.com/kb/en-us/solutions/public/7000/500/sol7559.html

 

 

Or you could use the after command in an iRule to set a timer in HTTP_REQUEST_SEND. The second example should give you a good start:

 

 

http://devcentral.f5.com/wiki/iRules.after.ashx

 

 

Aaron

Michael,

 

 

Agree that i dont want to over-complicate things... the main thing is to try and avoid a user sitting on a blank screen whilst the page is loading for more that 30 seconds... I'd rather throw a sorry page than have the user assume something else, or worse resubmit their request...

 

 

Hoolio: Cheers for that pointer, will have a read...

 

 

Cheers again

 

Gav