I have this config file that works in el7:

$ cat /etc/cgconfig.d/idle.conf
# Configuration file generated by cgsnapshot
group idle {
  perm {
    admin {
      uid = idle;
      gid = idle;
    }
    task {
      uid = idle;
      gid = idle;
    }
  }
  cpu {
    cpu.cfs_period_us="100000";
    cpu.cfs_quota_us="-1";
    cpu.shares="2";
  }
  cpuacct {
    cpuacct.usage="0";
  }
}

Running cgconfig in el8 doesn't seem to restore it. Is this a known bug? Is additional configuration needed somewhere else?