NiagaraAX Floating License Repository (FLR)

The FLR is a licensed feature that runs as a service in a Niagara station to provide licenses to other Niagara Runtime Environment (NRE) applications.

Figure 1. FLR service and property sheet view

In this environment, available licenses are “leased” by authorized NRE applications at startup and “returned” when the application shuts down. Figure 2 shows the basic FLR environment architecture. In the illustration, below, three licenses are being consumed by the two Hosts (Host A, Host B).

Figure 2. FLR environment architecture

The FLR environment is comprised of the following:

FLR server

The Floating License Repository (FLR) is a NiagaraAX service that runs in a user’s network environment to provide host–independent licensing for a limited number of NRE instances (FLR clients). The FLR server uses an LPF to provide licensing to properly configured FLR clients.
FLR client

Niagara applications run in the Niagara Runtime Environment (NRE) and include one or more instances of a Niagara station, workbench, driver, service, or other application. An FLR client is any NRE application instance that is configured to get its license from an FLR server.

Each client that is licensed by an FLR server “leases” one of the FLR server’s available licenses. If no licenses are available, the application will not start. When the NRE application instance closes, the license is “returned” to the FLR server and is available for any properly configured FLR client.
The concept of “instance” is very important. Each floating NRE application impacts the number of free licenses on the FLR.

When the FLR starts running, it reads the LPF and starts accepting FLR client requests for licenses. The FLR maintains the state of each license in the pack and responds to heartbeat messages from NREs that have a leased license. See also, About floating licenses and About the license pack file (LPF). Example FLR scenarios.

The system clocks on the FLR client and server must be within one minute of each other. If the system clocks differ by more than a minute, the client is not able to check out a license from the server. For this reason, it may be helpful to set up a time synch service for the server and clients. See the section About the NtpPlatformService in the NiagaraAX Platform Guide for more information about setting up a synchronized time service.

The following sections describe the primary characteristics of and procedures relating to the Floating License Repository (FLR):