# License Type

#### Using License from the System

You can use the license provided by the public cloud platform. After creating an ECS with a license authorized, you can use the authorized OS. The platform manages license compliance for you.

#### BYOL

What Is BYOL?

Bring your own license (BYOL) allows you to use your existing OS license. In such a case, you do not need to apply for a license again. In BYOL license type, you do not pay for the license fee when creating an ECS.

How to Use BYOL?

If you select the BYOL license type, you are required to manage licenses by yourself. The public cloud platform provides functions for you to maintain license compliance during the license lifecycle, for example, deploying ECSs on DeHs. If you have obtained an OS license, you do not need to apply for a license any more.

The OSs supporting BYOL are as follows:

- SUSE Linux Enterprise Server
- Oracle Enterprise Linux
- Red Hat Enterprise Linux

Application Scenarios

The system does not support dynamic license type changing. ECSs support BYOL in the following scenarios:

- Creating an ECS

  After creating an ECS, you cannot change its license type. If the license type must be changed, reinstall or change the ECS OS.

- Reinstalling an ECS OS

  When reinstalling an ECS OS, you can set the license type for the ECS.

- Changing an ECS OS

  When changing an ECS OS, you can set the license type for the ECS.

- Attaching a system disk

  The license type of a system disk is determined by the ECS license type after the ECS is created, the ECS OS is reinstalled, or the ECS OS is changed. If the system disk is detached and then attached to a new ECS or the original ECS, ensure that the ECS license type is the same as the system disk license type.

Parent topic: Security