Important Concepts for Kubernetes

 

Nodes 

Kubernetes runs your workload by placing containers into Pods to run on Nodes. A node may be a virtual or physical machine, depending on the cluster. Each node contains the services necessary to run Pods, managed by the control plane. 

Pods 

Pods are the smallest deployable units of computing that you can create and manage in Kubernetes. 

Deployments 

A Deployment provides declarative updates for Pods ReplicaSets. 

You describe the desired state in a Deployment, and the Deployment controller changes the actual state to the desired state at a controlled rate. You can define Deployments to create new ReplicaSets or to remove existing Deployments and adopt all their resources with new Deployments. 

ReplicationController 

A ReplicationController ensures that a specified number of pod replicas are running at any one time. In other words, a ReplicationController makes sure that a pod or a homogeneous set of pods is always up and available. 

Service 

An abstract way to expose an application running on a set of Pods as a network service. 

With Kubernetes you don't need to modify your application to use an unfamiliar service discovery mechanism. Kubernetes gives Pods their own IP addresses and a single DNS name for a set of Pods, and can load-balance across them. 

Ingress 

An API object that manages external access to the services in a cluster, typically HTTP. 

Ingress may provide load balancing, SSL termination and name-based virtual hosting.