Para CentOS 8 Stream execute o seguinte como root:
cd /etc/yum.repos.d/
wget https://download.opensuse.org/repositories/systemsmanagement:Uyuni:Master:CentOS8-Uyuni-Client-Tools/CentOS_8_Stream/systemsmanagement:Uyuni:Master:CentOS8-Uyuni-Client-Tools.repo
yum install obs-service-tar_scm
Para CentOS 8 execute o seguinte como root:
cd /etc/yum.repos.d/
wget https://download.opensuse.org/repositories/systemsmanagement:Uyuni:Master:CentOS8-Uyuni-Client-Tools/CentOS_8/systemsmanagement:Uyuni:Master:CentOS8-Uyuni-Client-Tools.repo
yum install obs-service-tar_scm