RHEL 8/9 new features and differences. 🆕

RHEL 8 vs. RHEL 9: New Features and Key Differences

Red Hat Enterprise Linux (RHEL) 8 and 9 are both enterprise-grade operating systems, but RHEL 9 builds on its predecessor with updated technologies, enhanced security, and improved cloud/edge capabilities. Below is a structured comparison:

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RHEL 8 (Released 2019)

Key Features:

1. Application Streams (AppStream):
   • Delivers multiple versions of software (e.g., Python 3.6, 3.8) via modular repositories.
   • Enables flexible software lifecycle management.
2. Package Management:
   • Uses YUM v4 (DNF backend) for faster dependency resolution.
   • Transition from Python 2 to Python 3 as the default.
3. Container Tools:
   • Introduced Podman, Buildah, and Skopeo as Docker alternatives.
   • Integrated with Red Hat Universal Base Image (UBI).
4. Security:
   • SELinux enhancements for policy management.
   • OpenSCAP for compliance auditing.
5. System Management:
   • Cockpit web console for GUI-based administration.
   • Stratis for simplified storage management.
6. Kernel & Hardware:
   • Linux kernel 4.18.
   • Support for 64-bit ARM (ARMv8-A), IBM Power, and x86_64.
7. Networking:
   • nftables replaces iptables for firewall management.
   • NetworkManager improvements for multi-host connectivity.

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RHEL 9 (Released 2022)

New Features & Enhancements:

1. Updated Kernel & Software Stack:
   • Linux kernel 5.14 for modern hardware support (e.g., Intel Alder Lake, AMD EPYC).
   • GCC 11, Python 3.9, OpenJDK 17, and Ruby 3.0 in AppStream.
2. Security Hardening:
   • Fapolicyd: Default application allow-listing to block untrusted executables.
   • Keylime: Remote attestation for edge/IoT device security.
   • SELinux performance optimizations and stricter defaults.
3. Edge Computing Focus:
   • Image Builder: Create customized OS images for edge deployments.
   • Minimal ISO for lightweight installations.
   • Over-the-air (OTA) updates via Web Console.
4. Container & Cloud Innovations:
   • Podman 4.0 with improved rootless containers and Quadlet for systemd integration.
   • Pre-configured cloud images for AWS, Azure, and Google Cloud.
   • Enhanced OpenShift and Kubernetes integration.
5. Performance & Scalability:
   • CPU and memory hot-add/remove for virtual machines.
   • Improved NUMA balancing and cgroup v2 support.
6. Networking:
   • Native WireGuard VPN support in the kernel.
   • NetworkManager SR-IOV configurations for virtual functions.
7. Developer Tools:
   • .NET 6.0 runtime and SDK.
   • Updated Git 2.37 and Git LFS 3.2.

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Key Differences Between RHEL 8 and 9

Aspect	RHEL 8	RHEL 9
Kernel Version	4.18	5.14
Python Default	3.6	3.9
Security	SELinux, OpenSCAP	Fapolicyd, Keylime, SELinux+
Edge Computing	Limited support	Image Builder, OTA updates
Container Tools	Podman 3.x	Podman 4.x, Quadlet
Cloud Integration	Basic cloud images	Optimized images for major clouds
Lifecycle	Full support until 2024	Full support until 2027

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Why Upgrade to RHEL 9?

• Modern Hardware Support: Better compatibility with newer CPUs/GPUs.
• Enhanced Security: Proactive threat prevention with fapolicyd and Keylime.
• Edge & Cloud Readiness: Streamlined tools for hybrid and edge environments.
• Performance: Kernel optimizations for scalable workloads.

Migration Considerations:

• Test compatibility of legacy applications with Python 3.9 and newer libraries.
• Update automation scripts (e.g., Ansible playbooks) for new Podman/network features.

For enterprises, RHEL 9 offers a future-proof platform for digital transformation, while RHEL 8 remains a stable choice for existing workloads.