ACE http redirect on probe fail & others

Question

Hi everyone,
I have multiple http based application running on 2 servers and they all be referenced behind the publised VIP from the load balancer.
The probes are already there, applications are accessed but one criteria from the business is not to fail the whole server for one application. There is some independance between the apps that if one fails, the other would need to still load balanced.
I would like, if the application fails on both server, to maybe be able to redirect to another URL any request for a particular App/URL.
Any suggestions ?

Answer 1

Hi,
To not declare a real server down if one of its applications fail, you should configure your probes in your serverfarm, and (if not already done) create a serverfarm per application.
If you want to be able to redirect a request send to a failed serverfarm, you can configure a backup serverfarm in you L7 policy map like this:
serverfarm name1 backup name2
The second serverfarm should then be of the type:
serverfarm redirect name2
webhost-redirection relocation_string [301 | 302]
where the relocation_string is the URL that should be used, 301 is permanently moved and 302 is temporarily.
For the relocation_string, you can use following special characters:
%h Inserts the hostname from the request Host header
%p Inserts the URL path string from the request
Mor info can be found in this doc:
http://www.cisco.com/en/US/docs/interfaces_modules/services_modules/ace/v3.00_A2/configuration/slb/guide/slbgd.html
Hope this helps.
Kr,
Dario