Three node(triad/redundant) RLKS Licensing server is a fail-over configuration that provide maximum uptime and availability of network licenses. This configuration need three separate machines/nodes located in the same data-center(recommended), running same Operating system(recommended) and same version of License server.
Having above said environment in place, License Administrator need to 'login' in to “Rational License key center” website to generate and download a license file for high availability RLKS environment. Apparently, PRIMARY, SECONDARY and TERTIARY node are decided in the order in which you enroll hostname and host-id data when you generate the license file. Subsequently, System Administrator need to download the license file and deploy(import) the SAME license file on ALL three Licensing server nodes.
Further going ahead, System Administrator has to start ‘License server service’ on ALL three nodes which eventually initiate heartbeat connection between 3-nodes to establish a quorum. what is quorum in Licensing server triad environment?
At least TWO License servers need to establish a connection out of three nodes in order to serve licenses to end-users/clients. Two License servers that form a quorum first, one out of them ACT as a MASTER License server which apparently serves the license keys. In case the MASTER License server goes down, the other two nodes try to establish a quorum between them to serve licenses to end-users/clients.
Now we have a good high level understanding of redundant RLKS License server deployment. Let me give you an overview of “IBM Rational Admin. and Reporting tool” high-level architecture from TRIAD/REDUNDANT RLKS perspective.
In a typical ART deployment scenario, you would have “Rational License key server Administration Agent” component on systems that have License server(RLKS) installed and on another node, an instance of “Rational License key server Administration and Reporting Server” component installed.
When all components of RLKS ART(License servers, ART Admin Agent, ART Admin Server) are installed on respective servers, you would have to login into ART Admin. server web console[https://Hostname:4743/rcladmin/Main.jsp] and add these servers as “redundant” cluster type and pass test connection between Admin and Agent nodes successfully.
Next action is “Start reporting” against each redundant license server node and this step in the background locate Master License server (out of three nodes)and create new log files( lmgrd.log.backup & ibmratl_timestamp.log) only on it.
Let me elaborate this point through an example, lets imagine that PRIMARY has formed a quorum with TERTIARY License server node, because TERTIARY can never be a MASTER License server, PRIMARY License server becomes the MASTER and serves licenses to users/client. When “Start Reporting” feature is started, reporting service create these files(below) ONLY on MASTER License server (here PRIMARY) -
In case of disaster/fail-over (PRIMARY goes down), SECONDARY becomes the MASTER (same set of files created on it). These log files data are crucial to do reporting because ART AGENT reporting service convert these logs data into a RDF data-set that is consumed by ART ADMIN server to get the desired reports.