CentOS 8 正式发布

CentOS 8 官方正式发布了！！！CentOS 完全遵守 Red Hat 的再发行政策，并且致力与上游产品在功能上完全兼容。CentOS 对组件的修改主要是去除 Red Hat 的商标及美工图。

该版本还包含全新的 RHEL upstream, CentOS Streams。

官方中文的发行说明：https://wiki.centos.org/Manuals/ReleaseNotes/CentOS8.1905

CentOS 8 主要改动和 RedHat Enterprise Linux 8 是一致的，基于 Fedora 28 和内核版本 4.18, 为用户提供一个稳定的、安全的、一致的基础，跨越混合云部署，支持传统和新兴的工作负载所需的工具。此次发布的亮点包括：

发行版

• 通过 BaseOS 和应用流 (AppStream) 仓库发布.
• AppStream 是对传统 rpm 格式的全新扩展，为一个组件同时提供多个主要版本

更详细介绍请看 Chapter 3, Distribution of content in RHEL 8 

软件管理

• YUM 包管理器基于 DNF 技术，提供模块化内容支持，增强了性能，并且提供了设计良好的 API 用于与其他工具集成

详细介绍请看 Section 5.1.4, “Software management” 

Shell 和命令行工具

• RHEL 8 提供了版本控制工具: Git 2.18, Mercurial 4.8, 和 Subversion 1.10.

详情请看 Section 5.1.6, “Shells and command-line tools” 

动态编程语言、Web 和数据库服务器

• Python 3.6 是默认的 Python 环境，有限支持 Python 2.7 
• Node.js 是在 RHEL 最新包含的，其他动态语言更新包括: PHP 7.2, Ruby 2.5, Perl 5.26, SWIG 3.0 
• RHEL 8 提供的数据库服务包括：MariaDB 10.3, MySQL 8.0, PostgreSQL 10, PostgreSQL 9.6, 和 Redis 5.
• RHEL 8 提供Apache HTTP Server 2.4 以及首次引入的, nginx 1.14.
• Squid 版本升级到 4.4 ，同时也首次提供Varnish Cache 6.0.

详细介绍请看 Section 5.1.7, “Dynamic programming languages, web and database servers” 

Desktop

• GNOME Shell has been rebased to version 3.28.
• The GNOME session and the GNOME Display Manager use Wayland as their default display server. The X.Org server, which is the default display server in RHEL 7, is available as well.

See Section 5.1.8, “Desktop” for more information.

Installer and image creation

• The Anaconda installer can utilize LUKS2 disk encryption, and install the system on NVDIMM devices.
• The Image Builder tool enables users to create customized system images in a variety of formats, including images prepared for deployment on clouds of various providers.
• Installation from a DVD using Hardware Management Console (HMC) and Support Element (SE) on IBM Z are available in RHEL 8.

See Section 5.1.2, “Installer and image creation” for further details.

Kernel

• The extended Berkeley Packet Filtering (eBPF) feature enables the user space to attach custom programs onto a variety of points (sockets, trace points, packet reception) to receive and process data. This feature is available as a Technology Preview.
• BPF Compiler Collection (BCC), a tool for creating efficient kernel tracing and manipulation programs, is available as a Technology Preview.

See Section 5.3.1, “Kernel” for more information.

File systems and storage

• The LUKS version 2 (LUKS2) format replaces the legacy LUKS (LUKS1) format. The dm-crypt subsystem and the cryptsetup tool now uses LUKS2 as the default format for encrypted volumes.

See Section 5.1.12, “File systems and storage” for more information.

Security

• System-wide cryptographic policies, which configures the core cryptographic subsystems, covering the TLS, IPsec, SSH, DNSSEC, and Kerberos protocols, are applied by default. With the new update-crypto-policies command, the administrator can easily switch between modes: default, legacy, future, and fips.
• Support for smart cards and Hardware Security Modules (HSM) with PKCS #11 is now consistent across the system.

See Section 5.1.15, “Security” for more information.

Networking

• The nftables framework replaces iptables in the role of the default network packet filtering facility.
• The firewalld daemon now uses nftables as its default backend.
• Support for IPVLAN virtual network drivers that enable the network connectivity for multiple containers has been introduced.
• The eXpress Data Path (XDP), XDP for Traffic Control (tc), and Address Family eXpress Data Path (AF_XDP), as parts of the extended Berkeley Packet Filtering (eBPF) feature, are available as Technology Previews. For more details, see Section 5.3.7, “Networking”.

See Section 5.1.14, “Networking” for additional features.

Virtualization

• A more modern PCI Express-based machine type (Q35) is now supported and automatically configured in virtual machines created in RHEL 8. This provides a variety of improvements in features and compatibility of virtual devices.
• Virtual machines can now be created and managed using the RHEL 8 web console, also known as Cockpit.
• The QEMU emulator introduces the sandboxing feature, which provides configurable limitations to what systems calls QEMU can perform, and thus makes virtual machines more secure.

See Section 5.1.16, “Virtualization” for more information.

Compilers and development tools

• The GCC compiler based on version 8.2 brings support for more recent C++ language standard versions, better optimizations, new code hardening techniques, improved warnings, and new hardware features.
• Various tools for code generation, manipulation, and debugging can now experimentally handle the DWARF5 debugging information format.
• Kernel support for eBPF tracing is available for some tools, such as BCC, PCP, and SystemTap.
• The glibc libraries based on version 2.28 add support for Unicode 11, newer Linux system calls, key improvements in the DNS stub resolver, additional security hardening, and improved performance.
• RHEL 8 provides OpenJDK 11, OpenJDK 8, IcedTea-Web, and various Java tools, such as Ant, Maven, or Scala.

See Section 5.1.11, “Compilers and development tools” for additional details.

High availability and clusters

• The Pacemaker cluster resource manager has been upgraded to upstream version 2.0.0, which provides a number of bug fixes and enhancements.
• In RHEL 8, the pcs configuration system fully supports Corosync 3, knet, and node names.

See Section 5.1.13, “High availability and clusters” for more information.

Additional resources

• Capabilities and limits of Red Hat Enterprise Linux 8 as compared to other versions of the system are available in the Knowledgebase article Red Hat Enterprise Linux technology capabilities and limits.
• Information regarding the Red Hat Enterprise Linux life cycle is provided in the Red Hat Enterprise Linux Life Cycle document.
• The Package manifest document provides a package listing for RHEL 8.
• Major differences between RHEL 7 and RHEL 8 are documented in Considerations in adopting RHEL 8.
• Instructions on how to perform an in-place upgrade from RHEL 7 to RHEL 8 are provided by the document Upgrading to RHEL 8.
• The Red Hat Insights service, which enables you to proactively identify, examine, and resolve known technical issues, is now available with all RHEL subscriptions. For instructions on how to install the Red Hat Insights client and register your system to the service, see the Red Hat Insights Get Started page.