RDP Preread

When using the RDP protocol, this module allows extracting cookies, which are used for session identification and management, before making a load balancing decision.

When building from the source code, the module must be enabled with the ‑‑with‑stream_rdp_preread_module build option. In packages and images from our repos, the module is included in the build.

Configuration Example

Binding to the Cookie-Issuing Server

This configuration uses the learn mode of the sticky directive:

stream {

    rdp_preread on;

    upstream rdp {

        server 127.0.0.1:3390 sid=a;
        server 127.0.0.1:3391 sid=b;

        sticky learn lookup=$rdp_cookie create=$rdp_cookie zone=sessions:1m;
    }
}

Directives

rdp_preread

Syntax	rdp_preread on | off;
Default	rdp_preread off;
Context	stream, server

Controls extracting information from RDP protocol cookies during the preread stage. If the setting is on, the variables listed below will be populated in the context where it is specified.

Built-in Variables

The semantics of cookie values depend on the RDP protocol version.

$rdp_cookie

The entire cookie value.

$rdp_cookie_<name>

The value of the cookie field with the specified name.