Red Hat Enterprise Linux (RHEL) has undergone significant transformations from version 7 to versions 8 and 9, reflecting the evolving demands of enterprise computing. Let's delve into the detailed differences between RHEL7 and RHEL8/RHEL9:
1. Kernel Version:
RHEL7: Initially shipped with Kernel version 3.1, offering fundamental capabilities but lacking newer features and optimizations.
RHEL8/RHEL9: Transitioned to more modern Kernel versions (4.18 in RHEL8 and 5.x in RHEL9), incorporating advancements in performance, security, and hardware support.
2. Package Management:
RHEL7: Utilized YUM (Yellowdog Updater, Modified) as the default package manager, providing basic package management capabilities with dependency resolution.
RHEL8/RHEL9: Adopted DNF (Dandified YUM) as the successor to YUM, offering improved performance, dependency resolution, and a cleaner interface for package management.
3. Default Filesystem:
RHEL7: Featured ext4 as the default filesystem, offering reliability, scalability, and performance suitable for various workloads.
RHEL8/RHEL9: Continued to use xfs (X File System) as the default filesystem, providing enhanced scalability, performance, and advanced features for modern storage environments.
4. Package Repository:
RHEL7: Offered a single repository for packages, limiting flexibility and choice in software installation and updates.
RHEL8/RHEL9: Introduced the BaseOS and AppStream repositories, providing a broader range of software packages and modules for streamlined application management and deployment.
5. Network Time Synchronization:
RHEL7: Relied on NTP (Network Time Protocol) for network time synchronization, ensuring accurate timekeeping across systems.
RHEL8/RHEL9: Transitioned to Chronyd as the default time synchronization solution, offering improved stability, accuracy, and flexibility compared to NTP.
6. Application Firewall:
RHEL7: Utilized Iptables as the default firewall solution, offering robust packet filtering capabilities for network security.
RHEL8/RHEL9: Adopted Nftables (nft) as the successor to Iptables, providing enhanced performance, scalability, and ease of management.
7. Firewalld Daemon Backend:
RHEL7: Used Iptables as the backend for the Firewalld daemon, enabling dynamic management of firewall rules.
RHEL8/RHEL9: Transitioned to Nftables as the backend for Firewalld, offering improved performance, flexibility, and compatibility with modern networking technologies.
8. Cockpit:
RHEL7: Did not include Cockpit, a web-based management tool, for system administration tasks.
RHEL8/RHEL9: Introduced Cockpit as a default feature, providing an intuitive web interface for system monitoring, configuration, and troubleshooting.
9. Container Service Support (Default):
RHEL7: Initially supported Docker as the default container runtime, enabling efficient and portable application deployment.
RHEL8/RHEL9: Transitioned to Podman as the default container runtime, offering a secure, lightweight alternative to Docker with full compatibility with OCI standards.
10. Changes in NFS:
RHEL7: Utilized /etc/sysconfig/nfs for NFS configuration, providing a centralized location for configuring NFS parameters.
RHEL8/RHEL9: Introduced /etc/nfs.conf as the primary configuration file for NFS, offering a more structured approach to NFS configuration management.
11. NFS UDP:
RHEL7: Supported UDP (User Datagram Protocol) for NFS communication, allowing for faster data transfers over the network.
RHEL8/RHEL9: Removed support for NFS UDP, emphasizing TCP (Transmission Control Protocol) for improved reliability and performance.
12. Network Script:
RHEL7: Supported network scripts for configuring network interfaces, providing flexibility in network configuration.
RHEL8/RHEL9: Deprecated network scripts in favor of NetworkManager, simplifying network configuration and management with modern tools and frameworks.
13. Username:
RHEL7: Supported Numeric User/Group names, allowing users to assign numerical identifiers to users and groups for system-level permissions and access control.
RHEL8/RHEL9: Removed support for Numeric User/Group names, encouraging adherence to standard alphanumeric naming conventions for user and group accounts.
14. securetty:
RHEL7: Included the securetty file for specifying terminals considered secure for root login, enhancing system security by restricting root access to designated terminals.
RHEL8/RHEL9: Removed the securetty file, adopting alternative security measures and authentication mechanisms for controlling root access.
15. Default Display Server
RHEL7: Xorg Traditional display server known for stability.
RHEL8: Wayland Modern replacement for Xorg, offering improved security and performance.
RHEL9: Gnome Integrates GNOME desktop environment for enhanced user experience and customization options.