Floating token licenses are based on the client-server paradigm; the token server issues tokens to client machines to run optimization jobs locally on the client machine.
Each client machine must have a client license file gurobi.lic that specifies where to find the Gurobi token server. This file typically contains a single line of text, containing the key TOKENSERVER set to either the Fully-Qualified Domain Name or the IP address of the token server.
This file needs to be located in a place where Gurobi can find it; please refer to Where do I place the Gurobi license file (gurobi.lic)? for more information.
As a failover option, clients may specify a pool of token servers by setting the TOKENSERVER key to a comma-separated list of servers, e.g.
TOKENSERVER=machine1,machine2,machine3
The servers will then be checked in sequence.
Note that each token server needs its own token server license. machine2 is also checked when machine1 is out of tokens, machine3 is checked when machine1 and machine2 are out of tokens (or when they are down).