Module 1: Introduction to OpenShift 4.19/4.20/4.21

Learning Objectives

By the end of this module, you will:

  • Understand what OpenShift Container Platform 4.19/4.20/4.21 is and its key benefits

  • Know the different installation methods available for bare metal deployments

  • Understand the workshop structure and learning path

  • Have a clear overview of prerequisites needed for deployment

  • Be ready to choose the appropriate installation method for your environment

Version Support Matrix

Always verify the current support status before deploying. Red Hat uses a Full Support → Maintenance Support → End of Life lifecycle for each minor release.

OpenShift 4.18 is approaching End of Life. New deployments should target 4.19, 4.20, or 4.21.
OpenShift Version Kubernetes Version Support Status Release Notes

4.18

1.31

Approaching EOL — Check lifecycle

4.18 Release Notes

4.19

1.32

Full Support

4.19 Release Notes

4.20

1.33

Full Support

4.20 Release Notes

4.21

1.34

Full Support

4.21 Release Notes

4.22 (upcoming)

1.35

Not yet released — Track on lifecycle page

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For the authoritative support timeline, see the Red Hat OpenShift Container Platform Life Cycle Policy.

Platform Architecture: Components & Benefits

Workshop Knowledge Graph
Figure 1. Platform Architecture

OpenShift 4.19/4.20/4.21: Enterprise Kubernetes Platform

OpenShift Container Platform 4.19/4.20/4.21 is Red Hat’s enterprise Kubernetes platform that provides a complete application platform for developing, deploying, and managing containerized applications.

Core Platform Foundation

  • Kubernetes 1.32/1.33/1.34: Container orchestration foundation

    • OpenShift 4.19 built on Kubernetes 1.32

    • OpenShift 4.20 built on Kubernetes 1.33

    • OpenShift 4.21 built on Kubernetes 1.34

    • Enhanced with enterprise-grade features and security

  • Red Hat Enterprise Linux CoreOS (RHCOS): Immutable operating system

    • Purpose-built for containerized workloads

    • Automatic updates and self-healing capabilities

    • Optimized for OpenShift Container Platform

  • Enterprise Integration: Security, monitoring, networking, and storage integrated out-of-the-box

    • Built-in security scanning and compliance

    • Integrated monitoring with Prometheus and Grafana

    • Software-defined networking with OVN-Kubernetes

    • Storage integration with OpenShift Data Foundation

Key Benefits for Bare Metal Deployments

Performance and Control

  • Direct Hardware Access: Maximum performance without hypervisor overhead

  • Custom Hardware Support: GPUs, FPGAs, and specialized networking hardware

  • Resource Optimization: Full control over CPU, memory, and storage allocation

  • Predictable Performance: Consistent performance for critical workloads

Enterprise Security

  • Hardware-Level Security: Secure Boot, TPM, and hardware encryption support

  • Network Isolation: Physical network segmentation capabilities

  • Compliance: FIPS 140-2/140-3 cryptography support

  • Air-Gapped Deployments: Complete disconnected operation support

Operational Efficiency

  • Automated Lifecycle Management: Seamless updates and maintenance

  • Self-Healing Infrastructure: Automatic recovery from failures

  • Unified Management: Single platform for VMs and containers

  • Cost Optimization: Eliminate hypervisor licensing and overhead

Key Features & Benefits

Why Choose OpenShift for Bare Metal?

Enterprise Security

  • Built-in security scanning and compliance

  • Pod security standards and network policies

  • FIPS 140-2/140-3 cryptography support

Operational Efficiency

  • Automated updates and lifecycle management

  • Self-healing infrastructure

  • Integrated monitoring and observability

Developer Productivity

  • Multiple programming languages and frameworks

  • Built-in container registry and build services

  • Comprehensive API and CLI tools

Bare Metal Advantages

  • Maximum performance with direct hardware access

  • Full control over infrastructure and security

  • Cost optimization for predictable workloads

  • Compliance with data sovereignty requirements

Installation Methods: Assisted vs Agent-based

OpenShift 4.19/4.20/4.21 provides two primary installation methods optimized for bare metal deployments covered in this workshop, both eliminating the complexity of traditional User-Provisioned Infrastructure (UPI). A third option, Installer-Provisioned Infrastructure (IPI) with BMC automation, is available for environments with full Baseboard Management Controller (BMC) integration and is documented in the official reference guides.

Modern Installer Advantages

Both installation methods provide significant improvements over traditional approaches:

  • Automatic Hardware Discovery: Discovery ISOs detect and validate hardware automatically

  • Virtual IP Management: Built-in VIP management eliminates external load balancer requirements

  • Real-time Validation: Continuous validation throughout the installation process

  • Flexible Topology: Support for Standard HA, Compact, Two-Node with Arbiter, and Single-Node deployments

The Agent-based Installer uses a rendezvous host that acts as a temporary bootstrap node during installation. The Assisted Installer manages its bootstrap process internally through the Red Hat console service.

Assisted Installer: Cloud-guided Installation

Best for: Connected environments with web-based management preference

Key Characteristics

  • Interface: Web-based console with guided workflow

  • Environment: Requires internet connectivity to Red Hat services

  • Automation: Automated validation, real-time monitoring, and smart defaults

  • User Experience: Intuitive UI suitable for all skill levels

Technical Features

  • Discovery Process: Automatic hardware detection and validation

  • Network Configuration: Simplified network setup with VIP management

  • Monitoring: Real-time installation progress tracking

  • Validation: Continuous pre-flight and installation checks

Documentation Reference

Agent-based Installer: Air-gapped Installation

Best for: Disconnected environments, custom configurations, and automation

Key Characteristics

  • Interface: Declarative configuration files and command-line tools

  • Environment: Supports fully air-gapped and disconnected deployments

  • Customization: Complete control over all installation parameters

  • Automation: Ideal for CI/CD integration and infrastructure-as-code

Technical Features

  • Configuration Files: install-config.yaml and agent-config.yaml for declarative setup

  • Mirror Registry: Built-in support for disconnected image mirroring

  • Agent ISO: Self-contained installation media with embedded configuration

  • Offline Operation: Complete installation without internet connectivity

Documentation Reference

Installation Method Decision Framework

Choose your installation method based on these key factors:

Factor Assisted Installer Agent-based Installer

Connectivity

Requires internet access

Supports air-gapped environments

Interface

Web-based GUI

Configuration files + CLI

Skill Level

Beginner to intermediate

Intermediate to advanced

Customization

Standard configurations

Full customization control

Automation

Manual web interface

CI/CD and automation friendly

Use Cases

Connected labs, POCs, standard deployments

Production, regulated environments, custom setups

Workshop Learning Path: Structured Approach

This workshop follows a knowledge-driven learning path designed around modern OpenShift deployment practices and the simplified infrastructure approach enabled by Assisted and Agent-based installers.

Learning Path Overview

Foundation Phase

  • Module 1 (Current): Platform architecture, installation methods, and workshop structure

  • Module 2: Simplified infrastructure preparation

Installation Phase (Choose Your Path)

  • Module 3: Assisted Installer deployment (connected environments)

  • Module 4: Agent-based Installer deployment (disconnected environments)

Configuration Phase

  • Module 5: Storage configuration with OpenShift Data Foundation

  • Module 6: Advanced networking configuration

  • Module 7: Optional features (Virtualization, AI/ML, VDDK migration)

Key Learning Principles

Knowledge Graph Approach

The workshop is structured as a knowledge graph where concepts build upon each other:

  • Core Concepts: OpenShift platform, RHCOS, and Kubernetes foundations

  • Installation Methods: Understanding the decision points and trade-offs

  • Simplified Infrastructure: Modern approach eliminating traditional complexity

  • Practical Implementation: Hands-on deployment and configuration

Decision-Driven Learning

Rather than covering all possible scenarios, the workshop guides you through decision points:

  1. Installation Method Decision: Based on your environment (connected vs disconnected)

  2. Cluster Configuration: Standard HA vs Compact vs Two-Node with Arbiter options

  3. Infrastructure Approach: VIPs vs external load balancers

  4. Advanced Features: Optional components based on your requirements

Modern Best Practices Focus

The workshop emphasizes current OpenShift deployment best practices:

  • Assisted/Agent-based Installers: Modern installation methods

  • Discovery ISO Boot: Automated hardware detection

  • Virtual IP Management: Simplified networking

  • Immutable Infrastructure: RHCOS-aware approaches

  • Declarative Configuration: Infrastructure-as-code principles

Workshop Outcomes

By completing this workshop, you will:

  • Understand OpenShift 4.19/4.20/4.21 architecture and benefits for bare metal

  • Choose the appropriate installation method for your environment

  • Deploy a production-ready OpenShift cluster using modern installers

  • Configure enterprise-grade storage and networking

  • Implement optional features like virtualization and AI/ML workloads

  • Apply best practices for ongoing cluster management

Prerequisites Overview

Before beginning the hands-on modules, you’ll need:

Account Requirements

Infrastructure Requirements

  • Bare metal servers meeting minimum specifications

  • Network infrastructure (DNS, load balancers)

  • Proper BIOS/UEFI configuration

Skills and Knowledge

  • Basic Linux system administration

  • Understanding of networking concepts

  • Familiarity with containerization concepts

Detailed verification procedures for all prerequisites are covered in Module 2.

Next Steps

Now that you understand OpenShift 4.19/4.20/4.21 and the workshop structure, you’re ready to begin the hands-on preparation.

Your Learning Path

  1. Complete Module 2: Infrastructure preparation and prerequisites verification

  2. Choose your installation method based on your environment:

    • Module 3 for Assisted Installer (connected environments)

    • Module 4 for Agent-based Installer (disconnected/custom environments)

  3. Configure storage and networking in Modules 5-6

  4. Explore optional features in Module 7

Documentation References

For additional information about OpenShift 4.19/4.20/4.21:

Continue to Module 2: Prerequisites and Infrastructure for OpenShift 4.19/4.20/4.21.