How to Reset Centos 7 Root Password?
You can reset the root password of your Centos 7 server with 2 different methods. If you want to reset with the first method, you must have access to the previous root password. If you know your previous root password, you can easily reset your server password via SSH(Putty). If you do not know your current root password, you need to contact the company you receive service from. Servers with unknown passwords require password reset via ESXI. I will tell you about password reset via ESXI in a different article. 
Resetting SSH password via console
Let's provide SSH access with the Putty program. Then, when we gain access, we can run the 'passwd' command and set a new password.
If you do not know how to provide SSH access, you can download the program from İndirme bağlantısını görmek için Giriş Yap veya Kayıt Ol. and provide the link as in the example I will give you. Generally, SSH ports are 22, you should request access information from the company you receive server service from.