Forum Discussion
rjonker
Nimbostratus
NimbostratusNeed help. HTTP monitor based on hostname
Hi,
When I create a basic HTTP monitor and use a hostname the result is that the actual ip address of the host is used in the monitor. A one time nslookup is done.
If the ip address of the host changes, the health monitor will fail.
Is there a way to use the hostename only all the time, by doing an nslookup every time?
I expect it can be done by an external script, but I was not able to find an example on DevCentral.
Please help!:D
3 Replies
hoolioCirrostratus
Does the web server have virtual host or host header definitions that require a specific hostname be inserted in all requests? I wasn't aware that any name resolution would be done for a monitor send string. I would have guessed that the static string would be sent in the monitor request. Can you clarify what you've tested and which version you've tested on?
Thanks,
Aaron
rjonkerI use this a health monitor to check the status of the ISP link on a Link Controller. I want to check that some internet web pages are reachable by just doing a "GET /".
If I configure the basic http monitor I type for instance www.nu.nl as the adress to be checked. If the monitor is now created I see that the ip address is put in there instead of www.nu.nl.
}
monitor HTTP-Nu {
defaults from http
transparent
dest 62.69.179.231:http
}
Now if www.nu.nl changes the ip address, the monitor will still check the old address and therefore fails.
So I need a script that can do an dns lookup first and then do the check on the resolved ip address.
BIGIP is running version: 9.4.5 with HF2 (soon to be upgraded to 10.0.1- hoolioI think you might need to use an external monitor. It would be a fairly simple one to implement using curl as long as you have DNS resolution configured. curl accepts a hostname and will perform name resolution before sending the request.
The Monitoring Codeshare has several examples of external curl-based HTTP monitors.
Aaron
