When deploying CentOS, the default behavior is to have the CentOS internet repositories available. If it is desired to not receive updates from CentOS’ internet site, create a postscript to execute one of the following commands:

Disable the repositories (requires yum-utils package to be installed):

yum-config-manager --disable CentOS-*

If yum-utils is not available, the repositories may instead be removed:

rm /etc/yum.repos.d/CentOS-*repo

If executing genimage multiple times, it may be required to delete the image between runs. This is due to certain assumptions that, among other things, could erase /etc/passwd without recreating the pertinent accounts.