About Kubernetes Objects

• Kubernetes objects are represented in Kubernetes API as well as .yaml format.
• Kubernetes objects are persistent entities in the Kubernetes system. 
• Kubernetes uses these entities to represent the state of your cluster, and describe following
  • What containerized applications are running and on which node.
  • What all resources are available to those applications.
  • Policies around for application behavior i.e.
    • Restart policies
    • Upgrade policies
    • Fault Tolerance policies
• By creating an object, you are effectively telling the Kubernetes system what you want your cluster's workload look's like and that is your cluster's desired state. 
• To work with Kubernetes objects i.e. create, modify or delete them. You have to use Kubernetes API. 
• When you use the kubectl command line call, which internally makes the Kubernetes API calls for you. 
• If you want to make Kubernetes API call directly in your own program then use respective programming Client Libraries.