# OpenShift Architecture Overview

Red Hat OpenShift is an enterprise Kubernetes platform that abstracts infrastructure complexity and delivers a self-service provisioning model across IaaS, PaaS, and container layers.

OpenShift Container Platform (OCP) is built on top of Kubernetes, adding enterprise-grade security, developer tooling, and multi-tenancy. On Kvant infrastructure, OpenShift serves as the primary interface between raw compute resources and tenant workloads.


# Platform Layers

Provisioning in OpenShift follows a structured top-down hierarchy. Each layer builds on the one below it, translating raw infrastructure into isolated, governed workload environments.

┌─────────────────────────────────────┐
│  4. Workload Layer                  │
│     Pods, Containers, Services      │
├─────────────────────────────────────┤
│  3. Namespace Layer                 │
│     Projects / Tenants              │
├─────────────────────────────────────┤
│  2. OpenShift Cluster Layer         │
│     Control Plane + Worker Nodes    │
├─────────────────────────────────────┤
│  1. Capacity Pool Layer             │
│     Machines, Storage, Networking   │
└─────────────────────────────────────┘
Layer Description
IaaS Physical or virtual machines, storage backends, and network fabric that form the raw resource foundation
OpenShift Cluster Control plane and worker nodes that aggregate IaaS resources and expose them to the Kubernetes scheduler
Namespace Logical tenant partitions that enforce resource quotas, RBAC policies, and cost boundaries
Workload Pods, containers, and services deployed by users within a namespace

# Key Concepts

ResourceQuota A Kubernetes object assigned per namespace that caps total CPU, memory, and storage consumption for a tenant.

LimitRange Sets per-pod and per-container resource defaults and maximums within a namespace, preventing any single workload from monopolising capacity within the Namespace.

Role-Based Access Control (RBAC) Ensures only authorised users and service accounts can deploy into a given Namespace.

Machine API OpenShift's interface for dynamically provisioning and deprovisioning cluster nodes, allowing the Capacity Pool to expand or contract based on demand.


# Related Pages