Forum Discussion

spalande's avatar
spalande
Icon for Nacreous rankNacreous
Jan 08, 2014

iRule not effective for existing connections

We have iRule for server maintenance window, where it will allow only GET requests and block all other requests. This works after applyig iRule to all VIPs. But whoever is already login into the webp...
application delivery
devops
iRules
hoolio's avatar
hoolio
Icon for Cirrostratus rankCirrostratus
Jan 08, 2014

thibino is correct that iRule changes only take effect on new connections.

You could leave the iRule enabled at all times, but use a data group to store an on|off value. The iRule would use the class command to check the data group key to see if non-GET requests should be blocked.

https://devcentral.f5.com/wiki/iRules.class.ashx

when HTTP_REQUEST {
    Check if the maintenance key is set to on in the maint_dg datagroup
   if {[class lookup "maintenance" maint_dg] eq "on"}{

       Check if this is not a GET request
      if {not ([HTTP::method] eq "GET")}{

          Send an HTTP response with cache control headers set to not cache the response
         HTTP::respond 200 content {Please retry your request later.  Maintenance!} Connection Close Cache-Control No-Cache Pragma No-Cache
      }
   }
}

Aaron