Architecture_of License Server

8/13/2019 Architecture_of License Server

http://slidepdf.com/reader/full/architectureof-license-server 1/11

LLiicceennssiinngg A Ar r cchhiitteeccttuur r ee:: A Ann OOvveer r vviieeww

By the Citrix Publications Department

Citrix® Systems, Inc.



Notice

The information in this publication is subject to change without notice.

THIS PUBLICATION IS PROVIDED “AS IS” WITHOUT WARRANTIES OF ANY KIND, EXPRESS ORIMPLIED, INCLUDING ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULARPURPOSE OR NON-INFRINGEMENT. CITRIX SYSTEMS, INC. (“CITRIX”), SHALL NOT BE LIABLE FORTECHNICAL OR EDITORIAL ERRORS OR OMISSIONS CONTAINED HEREIN, NOR FOR DIRECT,INCIDENTAL, CONSEQUENTIAL OR ANY OTHER DAMAGES RESULTING FROM THE FURNISHING,PERFORMANCE, OR USE OF THIS PUBLICATION, EVEN IF CITRIX HAS BEEN ADVISED OF THEPOSSIBILITY OF SUCH DAMAGES IN ADVANCE.

This publication contains information protected by copyright. Except for internal distribution, no part of thispublication may be photocopied or reproduced in any form without prior written consent from Citrix.

The exclusive warranty for Citrix products, if any, is stated in the product documentation accompanying suchproducts. Citrix does not warrant products other than its own.

Product names mentioned herein may be trademarks and/or registered trademarks of their respectivecompanies.

Copyright © 2006 Citrix Systems, Inc., 851 W Cypress Creek Rd, Ft. Lauderdale, Florida 33309 U.S.A. Allrights reserved.

Version History

April 12, 2006 Tammy Jones Original version

Licensing Architecture: An Overview ii



Table of Contents

ARCHITECTURE: AN OVERVIEW........................................................................................................................................ 1

SUMMARY...................................................................................................................................................................................1 I NTRODUCTION ........................................................................................................................................................................... 1 OVERVIEW OF CITRIX LICENSING ............................................................................................................................................... 1 LICENSING OPERATIONS OVERVIEW...........................................................................................................................................2 LICENSING ARCHITECTURE AND OPERATIONS ............................................................................................................................5

License Manager Daemon (lmgrd.exe).......... ........... .......... ........... .......... ........... .......... ........... .......... ........... .......... ........... .... 6 Citrix Vendor Daemon (Citrix.exe) ........................................................................................................................................ 6 Options File............................................................................................................................................................................6 Startup License....................................................................................................................................................................... 6 The Report Log....................................................................................................................................................................... 6 The Debug Log....................................................................................................................................................................... 6 License Files............... .......... .................................................................................................................................................. 6

THE LICENSE R EQUEST PROCESS ................................................................................................................................................ 7 Product Start-Up Phase ......................................................................................................................................................... 7

User Connection Phase..........................................................................................................................................................7 SUGGESTED READING............................................................................................................................................................8

Licensing Architecture: An Overview iii



Architecture: An Overview

Summary

This whitepaper provides you with details about the architecture of Citrix Licensing. It is one of a series ofwhitepapers designed to provide you with more detailed information for tasks that extend beyond the scope ofinstalling your licensing components and is designed to complement the Getting Started with Citrix LicensingGuide.

For a complete listing of the whitepapers, see the Getting Started with Citrix Licensing Guide in the CitrixKnowledge Base.

Introduction

Before you can use your Citrix product, you must install Citrix Licensing. Citrix Licensing is a system of componentsthat function together. This system includes the following:

• A license server: A system that allows licenses to be shared across the network.

• The license files: The files that you need to license your product. These files are stored on the licenseserver.

• The License Management Console: The optional Web-based interface you use to manage your licensefiles and your license server.

• Any product-side settings that are associated with the license server.

Overview of Citrix Licensing

Every Citrix product environment must have at least one shared or dedicated license server. License servers arecomputers that are either partly or completely dedicated to storing and managing licenses. Citrix products requestlicenses from a license server when users attempt to connect. The following diagram is an overview of a Citrixlicensing system. As shown in the diagram, servers running the various Citrix products contact the license server toobtain licenses:

Licensing Architecture: An Overview 1

http://support.citrix.com/article/ctx109108

http://support.citrix.com/article/ctx109108



This diagram shows two sets of servers pointing to a license server running the optional License ManagementConsole

When users connect to a Citrix product, it draws licenses from the license server. That is, the Citrix productrequests to check out a license from the license server on behalf of the user or client device. When the license issuccessfully 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 sharedwith 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 theproduct must be configured to communicate with that specific license server. The License Management Consolelets you manage and monitor your Citrix licenses by providing a user interface to the license server. You candownload licenses, display real-time inventories of licenses, run historical usage reports, and monitor alerts with theconsole. For more information about the License Management Console, see the Licensing: The LicenseManagement Console whitepaper in the Citrix Knowledge Base.

Licensing Operations Overview

The first time a user connects to a Citrix product, the product requests a license from the license server. When the

license server grants a license request, the Citrix product reserves a license for its use. Reserving licenses for thispurpose is known as checking out licenses. When the user logs off from the product server, the product returns thelicense to the license server. This process is known as checking in licenses.

Each time a Citrix product starts, it opens a connection to the license server by checking out the startup license.The startup license is a Citrix system file that enables Citrix products to maintain a continuous connection to thelicense server. The following figure shows that each product forms its own constant connection to the licenseserver.


http://support.citrix.com/article/CTX108660






The Citrix product makes a continuous connection to the license server. The license server can support up to 2000continuous connections.

For example, when a server running Presentation Server requests a license, the product retrieves the licenseserver name and port number information from the data store and establishes a connection to acquire theappropriate licenses.

The following figure provides a high-level illustration of the stages of the license checkout process for Citrixproducts.




A Citrix product goes through a three-step process to check out licenses: 1. At startup, a computer running a Citrixproduct checks out a startup license. 2. A client device connects to the product server. 3. The product requests alicense from the license server.

Citrix products, such as Presentation Server, 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, theproduct 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.

After a startup license is checked out by the Citrix product, the product and the license server exchange “heartbeat”messages every five minutes to indicate to each other that they are still up and running. If the product and thelicense server fail to send or receive heartbeats, the product lapses into the licensing grace period and licensesitself.

Some Citrix products can operate in a disconnected mode (not connected to the server). These products allow auser to check out a license and operate the product for a preconfigured period of time that is set by theadministrator. In this case, heartbeat messages are not exchanged. One example of disconnected mode is when auser checks out a Password Manager license for a laptop, and then uses the laptop when it is not connected to theserver. For products that operate in disconnected mode, the grace period takes effect after the preconfigured timespecified for the license check-out expires.




Licensing Architecture and Operations

The license server comprises several licensing components:

• The License Manager daemon

• The Citrix vendor daemon

• The License Management Console (optional)

• License files

• The options file

• The Citrix startup license

• The report log (optional) and the debug log

The following figure illustrates the way in which these components interact. A description of the components followsthe figure:

This diagram shows the Citrix product using TCP/IP to connect to license server components. License servercomponents include the License Manager daemon and Citrix vendor daemon, optional License Management

Console, debug log file, options file, report log file, and license files.

Two of the most significant licensing components are the License Manager daemon and the Citrix vendor daemon,which comprise the CitrixLicensing Service. These two processes handle licensing communication between theproduct and the license server.




License Manager Daemon (lmgrd.exe)

The License Manager daemon handles the initial contact with the Citrix product, passing the connection to the Citrixvendor daemon. It also starts the Citrix vendor daemon. The License Manager daemon uses TCP/IP port 27000 bydefault.

Citrix Vendor Daemon (Citrix .exe)

Licenses are granted by the Citrix vendor daemon, a process that runs on the license server. The Citrix vendordaemon tracks the number of licenses that are checked out and which product has them. Citrix productscommunicate with the Citrix vendor daemon using TCP/IP. By default, the Citrix vendor daemon uses a randomTCP/IP port. The port is chosen when the service starts.

Note: If the license server is behind a firewall, you must assign a static port to the Citrix vendor daemon. See theLicensing: Firewalls and Security Considerations whitepaper for information about assigning port numbers.

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 oflicenses a product server can use, the location of the system logs, and other user-defined customizations.

Startup License

The startup license (citrix_startup.lic) is a Citrix system file that:

• Allows product servers to maintain open connections to the license server

• Tracks which product servers are connected to the license server

• Stores licensing system information

Caution: Do not edit the startup license file, or any other license files, unless you need to change a Citrix vendordaemon or license server port number.

The Report Log

When enabled, the report log contains data about licensing activity, such as the number of licenses used. TheLicense Management Console uses the report log to generate licensing reports. If report logging is active, thereport logs must be archived regularly to prevent them from growing excessively large.

By default, the license server does not create report logs. To enable logging, see the Licensing: Generating UsageReports Using the Licensing: License Management Console whitepaper in the Citrix Knowledge Base.

The Debug Log

The debug log file records events, licensing transactions, and status and error messages for the License Managerdaemon and the Citrix vendor daemon. By default, license check ins and check outs are not recorded in the debuglog. For more information about the debug log and its role in troubleshooting, see the Licensing: Troubleshooting

whitepaper in the Citrix Knowledge Base.

License Files

License files are text files created by Citrix that store licensing data. They contain information about the productlicenses and the number of licenses, as well as system information such as the name of the license server. Thelicense server uses these files to determine whether or not to grant a license to a Citrix product.










The License Request Process

When a product requests a license from the license server, the Citrix vendor daemon determines whether or not alicense is available for the request. The following figure illustrates the license request process. Citrix PresentationServer is used as an example.

The license request process starts when a user connects to Presentation Server through a client device.Presentation Server then requests a license from the license server.

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 contacts the License Manager daemon to get the port number of the Citrix vendor daemon

• 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’srequest




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

Suggested ReadingThe following whitepapers provide more detailed information about some of the topics discussed in this paper:

Licensing: Getting Started with Citrix Licensing Guide

Licensing: Planning Your Deployment

Licensing: The License Management Console

Licensing: Generating Usage Reports using the License Management Console

Licensing: Troubleshooting












Architecture_of License Server

Documents

Transcript of Architecture_of License Server