Rewrite host header to specific pool member

I am picking up this project from Andy, and have had to reverse-engineer this irule back into our QA environment (runs the same version of code), and of course, it doesnt work there. I created the data class with the same name and syntax, just with the new IP addresses and string to lookup. the debug logs showthis:

 

 

Looked up 10.52.4.67, found: .

 

 

 

I will repost what what i have in the QA environment:

 

 

when HTTP_REQUEST_SEND {

 

 

Log debug messages to /var/log/ltm? 1=yes, 0=no.

 

set host_debug 1

 

 

Need to force the host header replacement and HTTP:: commands into the clientside context

 

as the HTTP_REQUEST_SEND event is in the serverside context

 

clientside {

 

 

if {$host_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: New [HTTP::method] request to [HTTP::host][HTTP::uri]"}

 

 

Look up the selected server IP in the datagroup to get the host header value

 

set host_header_value [findclass [LB::server addr] netenghosts " "]

 

 

if {$host_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: Looked up [LB::server addr], found: $host_header_value."}

 

 

Check if the lookup returned a value

 

if {$host_header_value ne ""}{

 

 

Replace the host header value

 

HTTP::header replace Host $host_header_value

 

if {$host_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: Replaced Host header with $host_header_value."}

 

}

 

}

 

}

 

 

class netenghosts {

 

"10.52.4.67 ims.next004pqa.services.qaprod.company.com"

 

}

 

 

I essentially copied and pasted from the production devices, so it doesnt appear that the irule or data class syntax is bad, yet persists in not finding the lookup value.

 

 

TIA

 

 

-clay

 

 

Hi Clay,

 

 

That looks valid. Can you confirm it's just a space between the IP address and host name in the datagroup?

 

 

Aaron

just to be sure, i went back and deleted/retyped those characters, and I get the same message in the ltm log:

 

 

Looked up 10.52.4.67, found: .

 

 

 

-clay

Not sure what the problem was, but here is how i fixed it:

 

 

1. created a new data group string with a different name

 

2. pasted in the same parameters.

 

3. updated the iRule to reference the new data group.

 

4. watched it work.

 

 

PFM

 

 

Thanks for keeping an eye on this and being willing to help.

 

 

-clay

That's quite odd. Glad you got it working regardless.

 

 

Aaron

Here's how I pulled it off:

when LB_SELECTED {

    set POOL [LB::server addr]

    log local0.debug "Pool Member is $POOL"

    switch $POOL {

        10.65.16.135 { HTTP::header replace Host "strv-int2.corp.lan" }

        10.65.17.62  { HTTP::header replace Host "strv-int4.corp.lan" }

        default { log local0.debug "Default hit on STRV-rewrite." }

    }

}