In addition to using a pre-built Gurobi cloud instance, you are welcome to use your existing Gurobi cloud licenses in your own internal cloud instance or in a public cloud. Please be aware that cloud instances with greater than 16 cores require a dual socket licensed version of Gurobi. Please see your Sales Manager or view our price list for more information.
If you use an elastic network interface (ENI) for a Linux instance, the key will remain valid. The recommended method is to create the instance with an ENI, then stop and start the instance as needed. This is explained here.
For a Linux instance, if you create an EC2 Elastic Network Interface, the license should remain valid when you stop and restart the instance using a larger machine type. For Windows, the license should remain valid when you stop and start the instance, without the need for an ENI. That said, if the license becomes invalid, you can request a license transfer, provided that you have purchased maintenance.