60 Red Hat OpenShift and IBM Cloud Paks on IBM Power Systems: Volume 1
4.1  OpenShift cluster components
Figure 4-1 shows an overview of the OpenShift container platform components.
Figure 4-1   Red Hat OpenShift cluster platform components
4.1.1  Docker service and Kubernetes
The Docker service that runs in every OpenShift cluster node provides the container image 
administration. The Kubernetes cluster provides cluster management and orchestrates 
containers on multiple nodes in the OpenShift cluster.
4.1.2  etcd store
The etcd store is a distributed key value store that is used by Kubernetes to store 
configuration and state information about the containers and resources that are inside the 
OpenShift cluster.
4.1.3  OpenShift-Kubernetes extensions
OpenShift-Kubernetes extensions are more resources that are used to save the OpenShift 
configuration and cluster internal state. These resource extensions are stored in etcd with 
application resources that are managed by Kubernetes.