6.3 is now available under the early deployment folder. The release notes provide a decent explination of the feature, but as is typical with the Aruba docs...it is a little confusing.
Centralized Licensing
Centralized licensing simplifies licensing management by distributing AP, PEFNG, RF PRotect, xSec and ACR
licenses installed on one controller to other controllers on the network. One controller to act as a centralized license
database for all other controllers connected to it, allowing all controllers to share a pool of unused licenses. The
primary and backup licensing server can share single set of licenses, eliminating the need for a redundant license set
on the backup server. Local licensing client controllers maintain information sent from the licensing server even if
licensing client controller and licensing server controller can no longer communicate.
You can use the centralized licensing feature in a master-local topology with a redundant backup master, or in a
multi-master network where all the masters can communicate with each other (for example, if they are all connected
to a single Airwave server). In the master-local topology, the master controller acts as the primary licensing server,
and the redundant backup master acts as the backup licensing server. In a multi-master network, one controller must
be designated as a primary server and a second controller configured as a backup licensing server.
Enable and configure this feature using the Configuration > Controller > Centralized Licenses tab in the WebUI,
or using the licensing profile commands in the command-line interface.
Primary and Backup Licensing Servers
Centralized licensing allows the primary and backup licensing server controllers share a single set of licenses. If you
do not enable this feature, the master and backup master controller each require separate, identical license sets. The
two controllers acting as primary and backup license servers must use the same version of ArubaOS, and must be
connected on the same broadcast domain using the Virtual Router Redundancy Protocol (VRRP). Other client
controllers on the network connect to the licensing server using the VRRP virtual IP address configured for that set
ArubaOS 6.3.0.1 | Release Notes Features Added in Previous 6.3 Releases | 25
26 | Features Added in Previous 6.3 Releases ArubaOS 6.3.0.1 | Release Notes
of redundant servers. By default, the primary licensing server uses the configured virtual IP address. However, if the
controller acting as the primary licensing server becomes unavailable, the secondary licensing server will take
ownership of the virtual IP address, allowing licensing clients to retain seamless connectivity to a licensing server.
Only one backup licensing server can be defined for each primary server.
Communication between the License Server and License Clients
When you enable centralized licensing, information about the licenses already installed on the individual client
controllers are sent to the licensing server, where they are added into the server’s licensing table. The information in
this table is then shared with all client controllers as a pool of available licenses. When a client controller uses a
license in the available pool, it communicates this change to the licensing server master controller, which updates
the table before synchronizing it with the other clients.
Client controllers do not share information about factory-installed or built-in licenses to the licensing server. A
controller using the centralized licensing feature will use its built-in licenses before it consumes available licenses
from the license pool. As a result, when a client controller sends the licensing server information about the licenses
that client is using, it only reports licenses taken from the licensing pool, and disregards any built-in licenses used.
For example, if a controller has a built-in 16-AP license and twenty connected APs, it will disregard the built-in
licenses being used, and will report to the licensing server that it is using only four AP licenses from the license pool.
When centralized licensing is first enabled on the licensing server, its licensing table only contains information about
the licenses installed on that server. When the clients contact the server, the licensing server adds the client
licenses to the licensing table, then it sends the clients back information about the total available licenses for each
license type. In the following example, the licenses installed on two client controllers are imported into the license
table on the license server. The licensing server then shares the total number of available licenses with other
controllers on the network. When new AP associates with a licensing client, the client sends updated licensing information to the server. The licensing server then recalculates the available total, and sends the revised license count back to the clients. If a
client uses an AP license from the license pool, it also consumes a PEFNG and RF Protect license from the pool,
even if that AP has not enabled any features that would require that license.