text: **2.4.3 Kubernetes operating environment, objects, and basic operations**
  
  This section describes the Kubernetes operating environment, including its objects and basic 
  operations. 
  
  **Master node**
  This node runs multiple controllers that are responsible for the health of the cluster, 
  replication, scheduling, endpoints (linking Services and Pods), Kubernetes API. It interacts 
  with the underlying cloud providers and others. Generally, it ensures that everything is 
  running and monitors worker nodes. 
  
  **Worker node**
  This node runs the Kubernetes agent that is responsible for running Pod containers by way of 
  Docker or rkt, requests secrets or configurations, mounts required Pod volumes, performs 
  health checks, and reports the status of Pods and the node to the rest of the system. 
  
  **Pod**
  Within a cluster, a pod encapsulates an application that is composed of one or more 
  processes from one and at time multiple containers. Every pod includes dedicated I/O 
  resources, such as storage, a unique IP, and a set of configuration properties for the runtime 
  environment. These features make pod the smallest unit of deployment and basic unit of 
  execution. 
  
  Docker is the most popular container run time that is used for Kubernetes Pod1. Depending 
  on associated containers, pods are available in the following types: 
  
  (cid:2) Pod with a single container: This configuration is the most common. 
  
  (cid:2) Pod with multiple containers: Must be colocated containers to serve a functional 
  requirement. 
  
  (cid:2) Networking: Each pod shares its namespace, IP, and port. However, for optimal 
  performance, containers in same Pod communicates with the localhost identity. 
  
  (cid:2) Storage: A pod specifies shared storage volume. All containers in a pod can share 
  persistent data through this volume. 