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richard_polyak's avatar
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Jun 04, 2024

VS with Wildcard Pool set path to specific port

Good Day - 


Today we have a Virtual Server listening on port 443, and an irule with 300+ lines to switch pool based on the path. Example of current irule is below:


  switch -glob [string tolower [HTTP::path]] {
     "/site1/score/sap/wbse/search" { pool pool_site1.test.com_34561 }
     "/site1/score/sap/companycodes" { pool pool_site1.test.com_34561 }
     "/site2/score/timekeeper/unionmasterdata/contract" { pool pool_site2.test.com_34562 }
     "/site2/score/timekeeper/unionmasterdata/jobcode" { pool pool_site2.test.com_34562 }
     "/site3/score/sap/chartofaccounts/glaccount*" { pool pool_site3.test.com_34563 }
     "/site3/score/timekeeper/timecard/gettimecard" { pool pool_site3.test.com_34563 }

        default {
            pool pool_site0.test.com_33333

So the above irule goes on for over 300+ more lines.

Here is the problem with this:


Above setup we are creating over 200+ individual pools of servers with the same 5 servers but just on different ports.

Original reason for all the pools is not every port would be up all the time so in the beginning it was simple just to create a pool, but now this is getting un-managable. 


What I would like to do is the following:

Since all the servers in the over 200+ pools are exactly the same but only on a different port I would like to create a wildcard pool instead with just the 5 servers in them.








Move the path / destination port into a Data group and create an iRule that will match the path then check if the server in the wildcard pool responds to the port and if so then send the request to that server.


So requesting assistance on creating an irule that:

  1. Read the path on the incoming request
  2. Match path in datagroup and map destination port based on path matched in datagroup
  3. Check if the servers in the wildcard server pool responds on the port matched
  4. if port responds on server, then send request to server that responds.

Any assistance would be appreciated.




1 Reply

  • Create datagroup (uri_to_port) for uri to port mapping

    ltm data-group internal /Common/uri_to_port {
        records {
            "/service1" { data "7070" }
            "/service2" { data "8080" }
            "/service3" { data "9090" }
        type string


    create app_pool with pool members with wildcard port and then use below iRule

    when HTTP_REQUEST {
        # Default port if not found in data group
        set port_number 443
        # Get the URI path
        set uri_path [HTTP::path]
        # Lookup the port number in the data group
        set port_number [class lookup $uri_path /Common/uri_to_port]
        # optional logging
        log local0. "Routing to port $port_number based on URI $uri_path"
        # Get the list of pool members
        set pool_members [members -list app_pool]
        # Initialize a flag to indicate if a node is selected
        set node_selected 0
        # Iterate through pool members to find an active one on the specific port
        foreach member $pool_members {
            # Extract the IP address from the member string
            set ip [lindex [split $member ":"] 0]
            # Check if the node is active on the specified port
            if {[active_members -node "$ip:$port_number"] > 0} {
                # Node is active
                set selected_member "$ip:$port_number"
                set node_selected 1
        # Check if a node was selected
        if {$node_selected} {
            #optional logging
            log local0. "Selected member: $selected_member"
            # Use the node command to forward traffic to the specific server and port
            node $selected_member
        } else {
            # No active members found, respond 503
            HTTP::respond 503 content "Service Unavailable"


    PS - This isn't tested iRule. Please test in non-prod environment before proceeding to PROD.