As we Install the OpenShift by Ansible method, identity provider is set to Deny all by default, which will deny access from all users. To allow access for users, you must choose another identity provider and configure the master configuration file. By default, the master configuration file is located at /etc/origin/master/master-config.yaml.
OpenShift has several identity providers which can help you to manager user authentication. I will use HTPasswd this time. You can find more information in
Configuring Authentication and User Agent
The htpasswd utility is provided in httpd-tools package.
# yum install httpd-tools
Need to restart
atomic-openshift-master to make the change to take effect.
# systemctl restart atomic-openshift-master