Licensing Server

Licensing Server -

 

Every Citrix product environment must have at least one shared or dedicated license server. License servers are computers that are either partly or completely dedicated to storing and managing licenses. Citrix products request licenses from a license server when users attempt to connect.

When users connect to a Citrix product, it draws licenses from the license server. That is, the Citrix product requests to check out a license from the license server on behalf of the user or client device. When the license is successfully checked out, the user can run the product.

Depending on the size and configuration of your product deployment, you may deploy licensing on a server shared with other applications, a dedicated license server, or multiple license servers.

License files must be located on the license server that is associated with the product you are licensing and the product must be configured to communicate with that specific license server. The License Administration Console lets you manage and monitor your Citrix licenses by providing a user interface to the license server. You can view a dashboard of licenses and alerts, import license files, and manage license server settings.

Citrix Licensing is a system of components that function together. This system includes:

• License server: A system that allows licenses to be shared across the network.
• License files: The files that you need to license your product. These files are stored on the license server.
• Console: The interface you use to manage your license files and your license server. For Licensing version 11.6.1 and later, this is the License Administration Console. (For previous versions, this is the License Management Console.)
• Product-side settings in your Citrix products that are associated with the license server.

 

There are three stages of the license checkout process.

A Citrix product goes through a three-step process to check out licenses:

1. At startup, a computer running a Citrix product checks out a startup license.
2. A client device connects to the product server.
3. The product requests a license from the license server.

Citrix products, such as XenDesktop, store a replica of the licensing information from the license server, including the number and type of licenses. If a Citrix product server loses its connection to the license server, the product enters a grace period and uses its local record of the licenses to continue licensing the product during the grace period. Citrix products update this record every hour.

License Server Components

The license server comprises several licensing components:

• Citrix vendor daemon
• Console
• License files
• Options file
• Startup license

Citrix Vendor Daemon

Licenses are granted by the Citrix vendor daemon (Citrix.exe), a process that runs on the license server. The Citrix vendor daemon tracks the number of licenses that are checked out and which product has them. Citrix products communicate with the Citrix vendor daemon using TCP/IP. By default, the Citrix vendor daemon uses TCP/IP port 7279.

License Files

License files are text files created by Citrix that store licensing data. They contain information about the product licenses and the number of licenses, as well as system information such as the name of the license server. The license server uses these files to determine whether to grant a license to a Citrix product.

Startup License

The startup license (citrix_startup.lic) allows Citrix products to communicate with the license server using a continuous open connection. The startup license:

·        Tracks which product servers are connected to the license server

·        Stores licensing system information

·        Does not affect your license count

Options File

The options file (Citrix.opt) is a license server configuration file that the Citrix vendor daemon reads every time it restarts or receives a command to reread the file. This configuration file defines licensing behavior—the number of licenses a product server can use, the location of the system logs, and other user-defined customizations.

The License Request Process

When a product requests a license from the license server, the Citrix vendor daemon determines whether a license is available for the request.

The license request process has two phases: the product startup phase and the user connection phase.

Product Start-Up Phase

·        When a Citrix product starts, it retrieves the license server location from its data store

·        The product connects to the Citrix vendor daemon

·        The product checks out a startup license

User Connection Phase

·        A user connects to a computer running the Citrix product

·        The product requests a license from the license server

·        The Citrix vendor daemon checks to see if any licenses are available and grants or denies the product's request

·        The license module in the product grants or denies the use of the product based on the response from the Citrix vendor daemon