What is the difference between Red Hat RHEL8 and RHEL7?
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1 Introduction
This article mainly explains the difference between Red Hat RHEL8 and RHEL7? We will explain the difference between RHEL8 and RHEL7 from multiple levels and multiple directions. This article also applies to the differences between CentOS8 and CentOS7. Many people refer to the difference between RHEL8 and RHEL7 as the difference between RHEL8 and 7
What is the difference between Red Hat RHEL8 and RHEL7
2. Comparison of Red Hat RHEL8 and RHEL7 features
Red Hat RHEL8 and RHEL7 feature difference comparison
2.1 The default file system
Both RHEL8 and RHEL7 use XFS
2.2 What are the kernel versions of RHEL8 and RHEL7
Regarding the kernel version, the differences between RHEL8 and 7 are as follows:
RHEL8 uses 4.18.0-x
RHEL7 uses 3.10-0-x
What are the kernel versions of RHEL8 and RHEL7
2.3 Kernel code name
Regarding the kernel code, the differences between RHEL8 and 7 are as follows:
RHEL8 adopts 2019-05-07 (Kernel Version 4.18.0-80)
RHE7 adopts 2014-06-09 (Kernel Version 3.10.0-123)
2.4 Standard/default warehouse channel
Regarding warehouse channels, the differences between RHEL8 and 7 are as follows:
RHEL8
Repo ID: rhel-8-for-x86_64-appstream-rpms
Repo Name: Red Hat Enterprise Linux 8 for x86_64 - AppStream (RPMs)
Repo ID: rhel-8-for-x86_64-baseos-rpms
Repo Name: Red Hat Enterprise Linux 8 for x86_64 - BaseOS (RPMs)
RHEL7
Repo ID: rhel-7-server-rpms
Repo Name: Red Hat Enterprise Linux 7 Server (RPMs)
RHEL8 and RHEL7 standard/default warehouse channel
2.5 Network time synchronization
Regarding network time synchronization, the differences between RHEL8 and 7 are as follows:
RHEL8
Only Chronyd is used, NTP deployment is not supported.
RHEL7
Both Chronyd and NTP support
The difference between RHEL8 and RHEL7 network time synchronization
2.6 Support the largest file
Regarding the largest file supported, the differences between RHEL8 and 7 are as follows:
RHEL8
The maximum file size supported by the XFS file system has been increased from 500 TiB to 1024 TiB.
(This maximum file size only applies to 64-bit machines. Red Hat Enterprise Linux does not support XFS on 32-bit machines.)
RHEL7
Max. (Single) File size = 500TiB
Max. File system size = 500TiB
2.7 Package Management
Regarding package management, the differences between RHEL8 and 7 are as follows:
Red Hat 8
Package management is done by DNF (YUMv4).
Yum4 is based on DNF technology, and the yum4 command provides backward compatibility with Yum v3 used in earlier versions. The yum command is just a symbolic link to dnf.
Red Hat 7
Yum is based on version 3.0.x
2.8 Maximum supported memory
Regarding the maximum supported memory, the difference between RHEL8 and 7 is as follows:
Red Hat 8
24TB, 64-bit architecture
Red Hat 7:
Only supports 12TB
2.9 Default network packet filtering
Regarding the default network packet filtering, the differences between RHEL8 and 7 are as follows:
RHEL8 uses nftables instead of iptables framework
nftables is the default network packet filtering, which replaces the previous iptables framework. The firewalld daemon now uses nftables as the default backend.
This will replace the previously used "iptables", "ip6tables", "arptables" and "ebtables" tools. "Nftables" does provide a single framework for IPv4 and IPv6 protocols.
The RHEL7 firewalld daemon uses iptables as its default backend.
2.10 Default database
Regarding the default database, the differences between RHEL8 and 7 are as follows:
The databases supported by RHEL8 by default:
- MySQL 8.0
- MariaDB 10.3
- PostgreSQL 10 and PostgreSQL 9.6
- Redis 5.0
MariaDB is the default implementation of MySQL in Red Hat Enterprise Linux 7
2.11 Supported hardware architecture
Regarding the supported hardware architecture, the differences between RHEL8 and 7 are as follows:
RHEL8 supports the following hardware architectures
- AMD and Intel 64-bit architectures
- The 64-bit ARM architecture
- IBM Power Systems, Little Endian
- IBM Z
RHEL7 supports the following hardware architectures:
- 64-bit AMD
- 64-bit Intel
- IBM POWER7
- IBM System z
2.12 Types of ISO images available for installation
Regarding the types of ISO images available for installation, the differences between RHEL8 and 7 are as follows:
RHEL 8 can be installed using the following types of ISO images:
- Binary DVD ISO
- Boot ISO
In RHEL7, the following available ISO images can be used for installation:
- Boot ISO
- Binary DVD ISO
- Supplementary Binary DVD
2.13 The installation status of the Cockpit web console by default
Regarding the installation status of the Cockpit web console by default, the differences between RHEL8 and 7 are as follows:
In RHEL8, Cockpit is installed and available by default. This will automatically install in non-minimal mode and enable the required ports in the firewall.
Cockpit provides an enhanced framework that can be used to access/edit/change many system settings. This provides access through a web interface, and you can use a browser to access the url address http://:9090 for management.
In the RHEL7 system, Cockpit is not installed by default and needs to be installed by enabling extra and optional repository channels.
In RHEL7 system, Cockpit is not installed by default
2.14 Default virtual machine management
Regarding the default virtual machine management, the differences between RHEL8 and 7 are as follows:
In RHEL8 system, it is managed by Cockpit by default. If necessary, you can also install virt-manager.
In the RHEL7 system, virt-manager will be used for KVM-based virtual system management.
2.14 Improvements in RMP version
Regarding the improvements of the RMP version, the differences between RHEL8 and 7 are as follows:
Red Hat Enterprise Linux 8 was released with RPM 4.14. Now, RPM verifies the contents of the entire package before starting the installation.
There are many improvements, some of the notable features are:
- The debuginfo package can be installed in parallel
- Support weak dependencies
- Support rich or Boolean dependencies
- Support package files exceeding 4 GB in size
- Support file trigger
Packages built on RHEL8 use a new SHA-256 hash on the compressed load.
And Red Hat Enterprise Linux 7 is released with RPM 4.11. On RHEL7, the RPM utility verifies the payload content of a single file when it is decompressed.
2.16 CUPS log
Regarding the CUPS log, the differences between RHEL8 and 7 are as follows:
All types of CUPS logs of RHEL8 are collectively recorded in the systemd journald daemon together with logs from other programs. To access the CUPS log, use the "journalctl -u CUPS" command.
On the RHEL7 system, CUPS logs are stored in the /var/log/cups directory.
Nobody user replaces nfsnobody
On the rhel8 system, the nobody and nfsnobody users and combinations are merged into nobodyID (65534).
In Red Hat Enterprise Linux 7, there are:
- Nobody user and group with ID 99
- The ID of the nfsnobody user and group pair is 65534, which is also the default kernel overflow ID.
2.17 The default version of the control system
Regarding the default version of the control system, the differences between RHEL8 and 7 are as follows:
RHEL 8 provides the following version control systems:
- Git 2.18
- Mercurial 4.8
- Subversion 1.10
Concurrent Version System (CVS) and Version Control System (RCS) are not available in RHEL8.
And Red Hat Enterprise Linux 7 is released with the three most popular open source revision control systems: Git, SVN, and CVS.
2.18 Programming language version
Regarding the programming language version, the differences between RHEL8 and 7 are as follows:
RHEL8 new version programming language
- - Python 3
- PHP 7.2
- Ruby 2.5
- Node.js 10
And RHEL7 supports the following editing languages
- Python 2 ( 2.7.X)
- PHP 5.4
- Ruby 2.0.0
2.19 Support for container technology
Regarding container technology support, the differences between RHEL8 and 7 are as follows:
Docker is not included in RHEL 8.0. When using containers, you need to use podman, buildah, skopeo and runc tools.
The podman tool has been released as a fully supported feature.
Docker and Docker Registry are part of the Extras subscription channel in Red Hat Enterprise Linux 7.
2.20 Development tool support
Regarding development tool support, the differences between RHEL8 and 7 are as follows:
RHEL 8 provides OpenJDK 11, OpenJDK 8, IcedTea-Web and various Java tools such as Ant, Maven or Scala.
In RHEL7, OpenJDK8 is used as the default Java Development Kit (JDK), and Java 8 is used as the default Java version.
2.21 NFS configuration comparison
Regarding the comparison of NFS configuration, the differences between RHEL8 and 7 are as follows:
The NFS configuration file of RHEL8 is /etc/NFS.conf.
When upgrading from RHEL7, Red Hat Enterprise Linux 8 tries to automatically convert all options from /etc/sysconfig/nfs to /etc/nfs. And no longer supports NFS/UDP.
In RHEL7, the default NFS configuration file is /etc/sysconfig/ NFS
2.22 The default display server
Regarding the default display server, the differences between RHEL8 and 7 are as follows:
In RHEL 8, the default display server used by Gnome display Manager is Wayland.
X.org server is the default display server in RHEL 7
3. Additional new functions and features of RHEL8
RHEL8 additional new functions and new features
3.1 The elevator kernel command line parameters are obsolete
Earlier versions of RHEL used elevator kernel command line parameters to set the disk scheduler for all devices. In RHEL 8, this parameter is deprecated.
The upstream Linux kernel has cancelled support for elevator parameters, but for compatibility reasons, it can still be used in RHEL 8.
3.2 Network scripts are deprecated
In RHEL 8, network scripts are not available by default. There is a new version of ifup and ifdown in use, which will require the NetworkManager daemon to run and use nmcli on the backend.
If you need early network scripts, you must install the "network-scripts" package.
RHEL8 network script is deprecated
3.3 The new kernel supports 5-level paging
In the early version, there is a 4-level paging implementation, which can handle 48/46-bit virtual/physical addresses, and the upper limit of the physical bus is 64TB. In the upcoming Intel processors, these restrictions have been extended to 57/52-bit virtual/physical memory addressing, with 128 PiB of virtual address space and 4 PB of physical memory capacity.
3.4 Anaconda supports system targets in RHEL 8
Previously, Anaconda did not provide system usage information to the subscription manager. In Red Hat Enterprise Linux 8.0, you can use Anaconda's system purpose window or Kickstart's syspurpose command to set the expected goals of the system during installation.
3.5 CodeReady Linux Builder Repository
There is a CodeReady Linux builder repository available for all RHEL subscriptions. This provides additional packages for developers. The packages included in the CodeReady Linux builder repository are not supported for production use.
3.6 Improved version of OpenSSH
The version of OpenSSH is 7.8p1, which has many improvements compared to earlier versions. Some of them are:
- SSH version 1 is no longer supported.
- DNS support is not turned on by default.
- The minimum acceptable RSA key size is set to 1024 bits.
- Remove'Blowfish','CAST','RC4' ciphers.
- The DSA public key algorithm is turned off by default.
3.7 Numeric user names and group names are not supported in RHEL8
The useradd and groupadd commands do not allow user names and group names to consist entirely of numeric characters. This is a feature not supported in RHEL7, and now RHEL8 does not support it at all.
3.8 Securetty is now disabled by default
The securetty PAM module is disabled by default, and the /etc/securetty file is deleted from RHEL8.
3.9 Improved TCP network stack
RHEL 8 has TCP network stack version 4.18, which can provide higher performance, better scalability and more stable performance. Performance has been improved, especially on busy TCP servers with high incoming connection rates.
In addition to the new TCP stack, there are two new TCP congestion algorithms. In most cases, BBR and NV can provide lower latency and better throughput than cubic.
3.10 High Availability (HA)
In Red Hat Enterprise Linux 8, pcs fully supports Corosync 3 cluster engine and Kronosnet (knet) network abstraction layer for cluster communication. Unable to upgrade cluster nodes from RHEL7 to RHEL8 in-place.
3.11 lvmlockd replaces clvmd
The clvmd used to manage shared storage logical volumes has been removed and replaced by lvmlockd (lvm lock daemon).
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