Disclaimer: I am not the developer of the Euler OS, nor the CentOS.

1. What is the Euler OS?
Euler OS is a Linux Distribution, based on CentOS, released by Huawei.

Is the Euler OS open-source?
No, Euler OS by Huawei does not have any public source code repository.

What is the license of the Euler OS?
Euler OS is licensed under the proprietary license by Huawei.

How do you find the license of the Euler OS?
I download the so-called Euler OS from here
And install it in the virtual machine. From the following path:
/usr/share/euleros-release/EULA
/usr/share/eula/eula.en_US
I find that it is Huawei's own license.

Does Huawei Change the EULA of the CentOS?
Yes, in the Euler OS, if type in the following command:
you can see it changed to "HUAWEI EulerOS-2.0"

2. What is the license of the CentOS?
According to CentOS Linux EULA
So what is the Distribution License of the CentOS?

Hello,

I have found the repository of the Euler OS in the Github, the developer claims it to be released under GPLv2.

So I open an issue here, asking the position of the source code.

I'm waiting the reply by the developer.

Hello

The developer has provided the repository at
http://developer.huawei.com/ict/site...os/source/2.2/

I have downloaded some source rpm package from the provided
repository, and can see the source file and headers.

So I think after finding the location of the source file, this issue
has been resolved.

The web site URL has been updated.