Overview of Containers

Why do we need Kubernetes

Question or Concerns about containers

• Containers are wonderful way of bundling and running your applications, But are they production ready?
• What would happen if container or the Docker Host goes down?
• How to make containers available 24*7 ?
• How to handle loads during peak time for the applications ?
• How to replace containers without having downtime with new Docker Image based containers ?
• How to monitor containers?

Solution to above Questions or Concerns

Wouldn’t it be good if there is some system which can help for handling all the questions/concerns raised in above section. That exactly what Kubernetes does.

• Kubernetes takes care of

  • Scaling requirements
  • failover
  • deployment patterns

• Kubernetes Provides

  • Service Discovery & Load Balancing
  • Storage Orchestration
  • Automated rollouts and rollbacks
  • Automated bin packing
  • Self-Healing
  • Secret & Configuration Management

• Kubernetes is not only for the open source community embraced containers, It is deeply embraced by the Cloud Providers.

  • Amazon Web Service offers Elastic Kubernetes Services(EKS)
  • Google Cloud platform offers Google Kubernetes Engine(GKE)
  • Microsoft Azure offers Azure Kubernetes Services(AKS)

What is Kubernetes

• Kubernetes is a platform that manages container-based applications, their networking and storage components.
• In Kubernetes, we focus on the application workloads rather than the underlying infrastructure.
• Kubernetes provides a declarative approach to deployments, backed by a rich set of APIs for management operations.
• Cluster: Cluster is collection of compute, storage and networking resources that Kubernetes uses to run workloads.
• Node: It is a single host. Now we can put the cluster as collection of nodes.
• Kubernetes has two kinds of Nodes
  • Master:
    • Provides core Kubernetes Services and orchestration to application workloads
  • Node:
    • run your application workloads

Kubernetes Cluster Architecture

What would be our approach with workloads in Kubernetes?

• We would be describing our application as YAML manifest and pass it to Kubernetes master from some client, and Cluster Master does the rest.

Pets Vs Cattle

I have found a interesting image in cloudrumblings.io, See the reference below

• In Kubernetes we follow cattle analogy and we would be discussing more in next series of articles