28 Red Hat OpenShift and IBM Cloud Paks on IBM Power Systems: Volume 1
/SM590000persistentVolumeClaim
/SM590000projected
/SM590000portworxVolume
/SM590000quobyte
/SM590000rbd
/SM590000scaleIO
/SM590000secret
/SM590000storageos
/SM590000vsphereVolume
NameSpace
Kubernetes NameSpace is set of virtual clusters that are backed by physical clusters. 
NameSpace is intended to divide cluster between users to provide an isolated and secure 
environment. NameSpaces are built with unique names. But the same name can be present 
in different NameSpaces. Therefore, a Name is supposed to be unique in a NameSpaces, but 
not so when it encounters NameSpaces. A NameSpace must not be nested.
Controller
Controller is another Kubernetes abstraction that handles the availability of a pod. Therefore, 
the most preferred practice is to use the Controller to manage pods. A Controller can create 
and manage multiple pods for you. It also can handle replication and rollout and provide 
self-healing capabilities at the cluster scope. For example, if a node fails, the Controller might 
automatically replace the pod by scheduling an identical replacement on a different node.
ReplicaSet
ReplicaSet is the process to maintain the configured availability level with a specified number 
of identical pods in the Kubernetes Cluster. A ReplicaSet must be created with a selector and 
the template to include specifications for pod instances to be created or deleted to meet the 
needed availability level. This task is performed by ReplicationController. A ReplicaSet 
identifies new pods to acquire by using its selector. 
Deployment
Kubernetes nodes are managed over declarative configuration to ensure the availability of the 
wanted number of pods or ReplicaSets. At times, a deployment also can be rolled back based 
on business requirements.
StatefulSet 
StatefulSets are API objects that are used to manage stateful application for deployment and 
ensures the ordering and uniqueness of pods. In this scheduling option, pods carry a unique 
identity, although it starts with identical pods. This scheduling can be helpful for the following 
aspects of an application:
/SM590000Persistent unique network identifier and storage
/SM590000Ordered deployment, scaling, and automated rolling updates
DaemonSet
A DaemonSet is another API server object that ensures scalability of a pod with the change of 
available nodes in the system. After a node is added to the cluster, the corresponding pod is 
initialized in that node. It also cleans up the pod after the node is deleted.