High Level View

The basic Kubernetes objects are as follows:

• Pod is the smallest deployable unit on a Node. It’s a group of containers which must run together. Quite often, but not necessarily, a Pod usually contains one container.
• Service is used to define a logical set of Pods and related policies used to access them.
• Volume is essentially a directory accessible to all containers running in a Pod.
• Namespaces are virtual clusters backed by the physical cluster.

There are a number of Controllers provided by Kubernetes. These Controllers are built upon the basic Kubernetes Objects and provide additional features. The Kubernetes Controllers include:

• ReplicaSet ensures that a specified number of Pod replicas are running at any given time.
• Deployment is used to change the current state to the desired state.
• StatefulSet is used to ensure control over the deployment ordering and access to volumes, etc.
• DaemonSet is used to run a copy of a Pod on all the nodes of a cluster or on specified nodes.
• Job is used to perform some task and exit after successfully completing their work or after a given period of time.

References