Added via https://github.com/openshift/openshift-docs/pull/8205. http://file.rdu.redhat.com/~adellape/031918/ocp39installupgrade4/install_config/install/advanced_install.html#running-the-advanced-installation-system-container http://file.rdu.redhat.com/~adellape/031918/ocp39installupgrade4/install_config/install/advanced_install.html#running-the-advanced-installation-docker
LGTM.