Of wizards and daemons, Part 2 – Understanding how Rational Common Licensing is designed
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After the wizardry of my previous post, where you learned how to install the Rational License Key Server Administration and Reporting Tool by using the IBM Installation Manager wizards, let’s now slay some demons! In this post, I will help you understand how a typical licensing model works and how, specifically, the Rational licensing model is designed, complete with daemons!
A licensing model generally consists of:
The license file defines what software or features the license is for, how long it is valid for, how many users can use the software, the computers on which the software can be used, and so on. The license file can be stored locally on the same computer as the application, or on a remote license server. In a served license model, where licenses are stored and served from a common license server, the applications that require a license connect over a TCP/IP network to obtain the licenses from the license server. Rational Common Licensing supports both options local license file deployment and the served license model.
The Rational Common Licensing model consists of the following components:
When you purchase an IBM Rational product, you receive a license entitlement that authorizes you to generate and download license files from the Rational License Key Center. The Rational License Key Center is an online service that you use to create license files (.dat, .upd, .txt) for the application or applications that you have purchased, or in IBM parlance, “have entitlement for”. As I mentioned earlier, the license file:
Tip: Do not change the host name when you migrate your license server from one computer to another. If you do change the host name, be sure to log into the Rational License Key Center, return your existing license and regenerate licenses for the new host computer.
For single desktop applications, you can store the licenses on the same computer as the application. You also have the option to run multiple instances of the application on the licensed computer. For applications that are used on several computers by different users, you can use a served license model. The licenses are held centrally by the Rational License Key Server and served up to requesting applications and users.
Let’s take the help of an illustration to clarify the concept of a served licensing model.
Fig 1: Rational Common Licensing process
Log in to the Rational License Key Center to generate and download your licenses. After you download the license files from the Rational License Key Center, you can use the Rational License Key Administrator (LKAD) to import and deploy the license files to the license server. Depending on your product type, you will need to use different mechanisms to point to the license server:
See the daemons in the illustration? Those two daemons - the lmgrd manager daemon and the ibmratl or telelogic vendor deamon - manage licenses on the license server. The lmgrd daemon runs on the license server. The vendor daemon information is supplied for each application in the license file for the application. The lmgrd deamon handles the initial contact with the client application or the IBM Rational product. It reads the license file, identifies and starts the appropriate vendor daemon, and then passes on the connection to the vendor daemon. The vendor daemon tracks how many licenses are checked out and who has the licenses. An application that requires a license connects to the license server and requests a license. The license server provides a license based on the availability of the license. The daemons write information about license usage to the lmgrd.log file. The License Key Server Administration and Reporting Tool uses the information in this log file to generate reports on license usage.
That, in a nutshell, is an overview of the Rational Common Licensing model. In my next post, I will pick up from where I ended here, and describe how the License Server Administration and Reporting Tool uses the log data and works with the license servers to generate reports.
Additional reading: If you are interested in more information on Rational Common Licensing, read my previous posts on the subject #licensing: