Currently each node monitors the cluster state for a license, and if it
does not find one, it sends a request to the master to generate a trial
license. However, the master node has this same logic. Since the master
node is the only thing that can change the cluster state, we know that
once some node becomes master, it will notice the lack of license,
generate a trial license, and send a cluster state update. The trigger
from every node telling the master to generate the trial license is not
needed.
This change removes the register_trial_license action that the non
master nodes used. It removes the need for the TransportService in the
LicensesService, which will help with deguicing.
Original commit: elastic/x-pack-elasticsearch@a71656847e
a9ace27107