Redirect

I don't think HTTP::uri or other HTTP request details are available in the LB_FAILED event. You could save the URI value in HTTP_REQUEST and then check it in LB_FAILED. Also, you can remove the double negative in the logic using something like this:

 
 when HTTP_REQUEST { 
  
     Save the URI to check in LB_FAILED 
    set uri [HTTP::uri] 
 } 
 when LB_FAILED { 
    if { [active_members [LB::server pool]] == 0 and not ($uri contains "/xyz/localservice")} { 
       HTTP::fallback "http://xyz.testabc.cgi.com" 
    } 
 } 
 

Aaron