Red Hat OpenShift — Introduction

Welcome to the OpenShift Tutorial

Red Hat OpenShift is an enterprise Kubernetes platform that extends upstream Kubernetes with developer and operational tools, security features, and a complete CI/CD pipeline. It’s built on top of Kubernetes but adds significant enterprise capabilities.

What is OpenShift?

OpenShift adds to Kubernetes:

• OpenShift Console — Full-featured web UI for cluster management
• Routes — Built-in ingress with TLS termination (similar to Ingress but more integrated)
• Source-to-Image (S2I) — Build container images directly from source code
• Operator Lifecycle Manager (OLM) — Manage Operators from OperatorHub
• Security Context Constraints (SCCs) — More restrictive than standard Kubernetes PSA
• Projects — Multi-tenant namespaces with quotas and RBAC

OpenShift vs Kubernetes

Feature	Kubernetes	OpenShift
Web console	Dashboard (basic)	Full-featured console
CLI	kubectl	oc (superset of kubectl)
Ingress	Ingress resource	Routes (+ Ingress support)
Image builds	External CI/CD	Built-in S2I, BuildConfigs
Security	PSA/PSP	SCCs (more restrictive)
Operators	Manual install	OLM + OperatorHub
Container runtime	containerd/CRI-O	CRI-O only
Updates	kubeadm upgrade	Over-the-air (OTA)

OpenShift Editions

Edition	Description
OpenShift Container Platform	Self-managed, on-premises or cloud
OpenShift Dedicated	Managed by Red Hat on AWS/GCP
Azure Red Hat OpenShift (ARO)	Managed jointly by Microsoft and Red Hat
ROSA	Red Hat OpenShift on AWS (managed)
OpenShift Local (CRC)	Single-node for local development

Prerequisites

Before starting this tutorial, you should have:

• Completed the Kubernetes Foundation Tutorial
• OpenShift Local (CRC) for hands-on practice
• A Red Hat account (free developer account)
• oc CLI installed

Installing OpenShift Local (CRC)

# Download from Red Hat Developer portal
# https://console.redhat.com/openshift/create/local

# Setup (one-time)
crc setup

# Start the cluster
crc start

# Get credentials
crc console --credentials

# Login with oc CLI
eval $(crc oc-env)
oc login -u developer -p developer https://api.crc.testing:6443

What You’ll Learn

1. OpenShift architecture and how it extends Kubernetes
2. Managing Projects, Users, and RBAC with OpenShift
3. Routes for exposing applications with TLS
4. Building images with S2I and BuildConfigs
5. Managing Operators via OLM and OperatorHub
6. Security Context Constraints (SCCs)
7. CI/CD with Tekton Pipelines and GitOps with ArgoCD

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Practice Questions

Q1: How does the OpenShift CLI (oc) relate to kubectl?

Show Answer

The `oc` CLI is a **superset of kubectl**. Every `kubectl` command works with `oc`. Additionally, `oc` adds OpenShift-specific commands: - `oc new-project` — Create a project (namespace with extras) - `oc new-app` — Create an application from source, image, or template - `oc expose` — Create a Route to expose a Service - `oc adm` — Administrative commands - `oc login` — Authenticate to the cluster

Q2: What is a Route in OpenShift and how does it differ from a Kubernetes Ingress?

Show Answer

A **Route** is OpenShift's native way to expose Services externally. It predates Kubernetes Ingress and provides: - Built-in TLS termination (edge, passthrough, re-encrypt) - Automatic hostname generation - Tighter integration with OpenShift's HAProxy router While OpenShift also supports standard Kubernetes Ingress resources, Routes are the preferred and more feature-rich option.

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OpenShift Overview ← Next: OpenShift Architecture →