Warning: user mockbuild does not exist: using root

The ‘mock’ module is responsible to build the source RPMs (SRPMs) under a chroot environment and uses the ‘mockbuild’ user.
If the mockbuild user does not exist while installing the source RPM, you will receive the ‘Warning: user mockbuild does not exist. using root‘ error message.

In order to fix the warning message, install the ‘mock’ module:

# yum install mock

and create the ‘mockbuild’ user

# useradd -s /sbin/nologin mockbuild

Once done, you should be able to install the required tool under the mockbuild user.