Although Selenium Grid is the most popular browser automation architecture nowadays - it is neither the most suitable for Openshift, nor the most efficient one. Selenium Grid is storing running sessions list in memory thus making it impossible to have several replicas behind reliable load balancer. This makes traditional Selenium Grid in Openshift not fault-tolerant.
One possible (commercial) alternative is Moon - an efficient Selenium solution made particularly for container management platforms such as Openshift and Kubernetes. Moon is a bulletproof stateless solution that can have an unlimited number of pods being run in parallel behind load balancer. Documentation with deployment instructions is here.