Failover License Server Setup

RLM supports the notion of a failover license server, unlike FlexNet Publisher, which supports triple-redundant license servers instead. This allows for a second license server to run, monitoring the health of the primary server. If the primary server goes down (i.e. the machine is offline and unreachable), the failover server will begin serving out the licenses. If the failover capability is desired, please state so in the license request and provide the name and host ID of the failover machine. See below for more on setting up a failover server environment.

Altair discourages the use of the failover server. Instead, in case of failure of the RLM subsystem, the Altair Accelerator software allows a 5 day grace period to recover the licensing, which should be enough time to either restore the main license server or to move the license server to a new machine.

If a failover license server is to be implemented, use the following guidelines.

  1. Create the license server directory, as explained above, on the failover server host.
  2. Copy both the failover license (rtda_failover.lic) and the original license (rtda.lic) into this new directory. The original file must use a .lic extension for failover to work.
  3. Edit both license files to ensure the path to rtdad in the ISV line is correct. The port in the failover license may also be modified if so desired.
    Example of an RLM Fail-Over License
    HOST rtdafailover 001d60ed1555 9090
    ISV rtdad /local/disk/rtda/license/rtdad
    LICENSE rtdad rlm_failover 1.0 permanent 1 hostid=0017f230ec7a
    _failover_host=rtdalicsrv sig="60P0450F3HSW4GJJAKNNMC...
    ...2GJNDUKJBUPFEPTR9UYK3DAWFBY3F348NC"

    The "hostid=" and "_failover_host=" values must be those of your primary server.

  4. Start the failover server:
    > source /<install_path>/<version>/<platform>/common/etc/vovrc.csh
    % ./rlm -nows >& rtda_failover.log &
  5. If the original server fails and you want to use the failover server, you can use the browser interface /cgi/license.cgi to change the value of RLM_LICENSE used by both vovserver and vovtasker. Remember that you have 5 days from the failure of the original server to decide the switch to the failover server.
    % setenv RLM_LICENSE 7070@original_server:7070@failover_server
  6. To change the value of RLM_LICENSE in a running server, you can use vtk_server_setenv from the command line:
    > source /<install_path>/<version>/<platform>/common/etc/vovrc.csh
    % vovsh -x "vtk_server_setenv RLM_LICENSE 7070@failover_server"
The failover server will take over only if the original host is down, so it may be hard to test the failover capability. The migration to the failover server takes up to 3 minutes, during which there will be no access to licenses.
Important: For the secondary license server to take over, the primary server host must effectively be off the network, that is, shut down or with its network connection severed. The secondary host will not take over if RLM is simply not running on the primary host. Also, there must have been at least about 2 minutes where both license servers were up, so that the failover server can learn the features to be served.