There are multiple options to configure OpenShift integration with an IDP. Usually one would use something like an LDAP, AD (Active Directory) for use in a production cluster or a corporate environment. This guide is a basic how-to in configuring using the htpasswd file which is one of the IDP integration options in Openshift 4.x.
htpasswd is a tool used to create and update the flat-files used to store usernames and password for basic authentication of HTTP users. These flat-files are commonly used by the Apache HTTP Server, as well as some other server software, to provide password protection for web content.