02 | Kubernetes Architecture

What are main components of K8s?

Here is hierarchy of components:

• Cluster: 
  • Node: Cluster have set of Nodes
    • Node can be of two type:
      • Master Node
      • Worker Node
        • POD: Work Node run container instances in form of POD.

What is a Node?

A node is a machine – physical or virtual – on which Kubernetes is installed.

What is a Cluster?

A cluster is a set of nodes grouped together. 

What is Master Node?

A cluster have at-least one Master Node.

Master keeps a look over the worker nodes in the cluster and is responsible for the actual orchestration of containers on the worker nodes.

When we say look over, we means Master Node:

• Monitors
• Controls/Manage
• Schedule Containers
• Ensure Replication of Containers
• Ensure Scaling of Containers
• Expose APIs

What is the role of Worker Node?

Worker Node Functionality

• Runs Containers
• Contains Container Runtime
• Accept request to run/destroy containers
• Also called as Minions

What is a POD?

• POD is smallest Deployable Unit
• Containers are not directly deployed in Kubernetes on Worker node but deployed as Pod
• Single Pod can contain one or more Containers.
• Characteristics of containers deployed in one POD:
  • Share environment
  • Share Volumes
  • Share IP Address
  • Share lifecycle (live together, die together)
  • Scheduled on the same worker node