CentOS 7 and Red Hat 7 use the 3.10 kernel (later than 3.8), and the dracut-modules-growroot package is not required. You only need to install Cloud-Init and cloud-utils-growpart. Cloud-Init has been installed in section Installing Cloud-Init.
This section uses CentOS 7.3 as an example to describe how to install the packages. The procedure also applies to other OSs.
[root@localhost ~]# rpm -qa | grep cloud-init cloud-init-0.7.5-10.el7.centos.1.x86_64 [root@localhost ~]# rpm -qa | grep growpart [root@localhost ~]#
yum install cloud-utils-growpart
[root@localhost ~]# rpm -qa | grep growpart cloud-utils-growpart-0.29-2.el7.noarch