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Overview

Kubernetes is a portable, extensible, open source platform for managing containerised worklaods and services that facilitates both declarative configuration and automation. It has a large, rapidly growing ecosystem.

Traditional Deployment Era → Organisations ran applications on physical servers. No way to define resource boundaries for applicaitons in a physical server, this caused resource allocation issues. Different applications could be run on different physical servers, but this did not scale, resources were underutilised.

Virtualised Deployment Era → As a solution, virtualisation was introduced. could run multiple VMs on a single physical server’s CPU. Allows vetter utilisation of resources in a physical server and allows better scalability because an app can be added or updated easily. Each VM is a full machine running all the components, including its own operating system, on top of virtualised hardware.

Container Deployment Era → Have relaxed isolation properties to share the OS. Containers are considered lightweight. They are decoupled from underlying infrastructure, they are portable across clouds and OS distributions.

Container Benefits

• Agile application creation and deployment: increased ease and efficiency of container image creation compared to VM image use.
• Continuous development, integration, and deployment: provides for reliable and frequent container image build and deployment with quick and efficient rollbacks (due to image immutability).
• Dev and Ops separation of concerns: create application container images at build/release time rather than deployment time, thereby decoupling applications from infrastructure.
• Observability: not only surfaces OS-level information and metrics, but also application health and other signals.
• Environmental consistency across development, testing, and production: runs the same on a laptop as it does in the cloud.
• Cloud and OS distribution portability: runs on Ubuntu, RHEL, CoreOS, on-premises, on major public clouds, and anywhere else.
• Application-centric management: raises the level of abstraction from running an OS on virtual hardware to running an application on an OS using logical resources.
• Loosely coupled, distributed, elastic, liberated micro-services: applications are broken into smaller, independent pieces and can be deployed and managed dynamically – not a monolithic stack running on one big single-purpose machine.
• Resource isolation: predictable application performance.
• Resource utilization: high efficiency and density.

What Kubernetes Can Do