Kubernetes lets u create, update, delete containers. It is a container orchestration engine ( orchestration here refers to starting/stopping containers.

Why Kubernetes ?

It is cloud native that means all cloud support a lot of K8s api

K8s Cluster

It is a fleet of servers that can talk to each other. Creating a K8s cluster is equivalent to starting bunch of machines that’s running K8s code having each other’s address.

Deployment in K8s

Nodes

Each machine that are part of K8s Cluster are referred as node.

Master Node vs Worker Node

• Master Node ( Machine that is running bunch of servers , DB )
  • Developer talks to this node. It takes declarative/ desired state command from developer. These commands are written in manfest.yml file. Commands to create, update, delete pods
  • It schedules starting of pods in worker nodes.
  • If a worker node dies master node moves the pod to other worker node based on availability.

Master Node Architecture

Worker Node Architecture

Its constantly checking on master node. Is there a new job for me ? Am I supposed to start/stop something new ?

Pods

Whenever u want to start a container u are actually starting a pod than can run multiple containers together.