iRule for sorry page with pool and path

Hi again!

Here's some comments:

    when LB_FAILED {
            LB failed is triggered when the load balancer
            is unable to choose a member for the connection (no available 
            members, or too many retries due to server connection issues

            Set the variable failed to 1 so we can check it later in the response
            set failed 1

            Rewrite the uri to whatever you want it to be. 
            The client would still see whatever they had from before

            HTTP::uri "/maintenance/maintenance.html"

            Select the pool you want to serve the maintenance page
            pool mov_maintenance_page
        }
    }

    when HTTP_RESPONSE {
        Check if the LB failed event has been triggered by checking if
        the variable failed exists and is set to 1
        if { [info exists failed] && $failed == 1 } {
            Close the connection to make sure that the user makes a new connection
            HTTP::close
        } 
    }
`

The problem with this setup, which I might mention too, is that you would be unable to send any pictures with the sorry page, unless you encode them with base64 within the html content OR use a CDN to deliver them.

Reason:

ol

Instead you might want to qualify incoming requests for the sorry page content directory before rewriting the uri:

`    when LB_FAILED {
            LB failed is triggered when the load balancer
            is unable to choose a member for the connection (no available 
            members, or too many retries due to server connection issues

            Set the variable failed to 1 so we can check it later in the response
            set failed 1

            If the client does not request resources in the maintenance
            folder, then rewrite the uri. Otherwise, let it pass through as the 
            content reqests belongs to the maintenance page

            if { !([HTTP::uri starts_with "/mov") } {
                HTTP::uri "/mov"
            }

            Select the pool you want to serve the maintenance page
            pool mov_maintenance_page
        }
    }

    when HTTP_RESPONSE {
        Check if the LB failed event has been triggered by checking if
        the variable failed exists and is set to 1
        if { [info exists failed] && $failed == 1 } {
            Close the connection to make sure that the user makes a new connection
            HTTP::close
        } 
    }


From a design perspective I would consider delivering the sorry page content directly from the F5 though using HTTP::respond and content from the CDN, because when there's a server side problem, there's also a risk that your sorry pool members is affected too.
/Patrik