CentOS 8 Features

 

Kernel

CENTOS 8 is running on kernel version 4.18 and based on Fedora 28.  

Control Group V2 

is supported that manages and distributes system resources in a better way compared to the previous version. Control group v2 has only single hierarchy that categorizes processes based on the role of the owner thereby removes the conflicts policies arising due to multiple hierarchies.

 

Enhancement in sosreport and kdump is also done. CENTOS 8 now supports early kdump compared to previous versions in which kdump was not able to capture crash information early. eBPF based programs and maps can be reported using sosreport. 

Supported CPU Architectures are:

  • AMD and Intel 64-bit architectures
  • The 64-bit ARM architecture
  • IBM Power Systems, Little Endian
  • IBM Z

Support for 5-level paging now enables CENTOS 8 to  supports upto 4 PB of physical memory. Earlier version CENTOS 7 has 4 level paging that allows addressing space of 256 TiB, same has been increased to 128 PiB and thus increasing physical address space up to 4 Pib

 

Software Management

CENTOS 8 offers improvement for package management tool yum, which is now based on DNF  (Dandified Yum) technology that is advanced and has better performance with support for modular content. RPM version 4.14 is distributed in  CENTOS 8 and rpm now validates the package content before starting the installation. Support for packaging files above 4GB in size is added.

 

dnf

 utility allows to install, upgrade packages.

 

 

# dnf install 

 

# dnf update

 

# dnf upgrade

 

dnf provides 

  • Increased performance

  • Support for modular content

  • Well-designed stable API for integration with tooling

 

Content Distribution

Red Hat Enterprise Linux 8 has two modes of Content distribution and will only need two repositories enabled.

  • BaseOS repository

     – The BaseOS repository provides the underlying core OS content in the form of traditional RPM packages. BaseOS components have a life cycle identical to that of content in previous Red Hat Enterprise Linux releases.

  • AppStream repository 

    – The Application Stream repository provides all the applications you might want to run in a given userspace. Other software that has special licensing are available on a Supplemental repository.

 

What is AppStream?

The AppStream allows you to install additional versions of software on independent life cycles and keep your operating system up-to-date while having the right version of an application that suits your use case. Note that no two streams can be installed at the same time into the same userspace.

Application Streams are typically named according to the version of software it distributes e.g. mongodb:3.4 or mongodb:3.6, but may also use names such as 

“latest”

 and “

stable”

 and “

latest

“.

 

 

File Systems and storage 

XFS file system supports shared copy-on-write data extent functionality that allows sharing a common set of data block for two or more files that is Fast and  space efficient. LUKS2 replaces the legacy LUKS1 format. LUKS2 provides encrypted volumes that supports auto recovery in case of metadata corruptions.

Stratis is new local storage manager that provides managed file systems on top of pools of storage that simplifies tasks like Managing snapshots, expanding file systems on the fly, XFS is default file system used by stratis. 

https://www.youtube.com/watch?v=9lMifqB6Y8s

 

Cockpit

CENTOS 8 is having pre-installed cockpit packages on non minimal installations as well as firewall ports are opened, Package can be obtained from CENTOS default repositories for minimal installations. Cockpit’s web interface can be used for managing machines remotely easily.

Cockpit is now compatible with mobile browsers, thus managing systems using mobile devices is possible now. Cockpit’s page now warns and  informs about missing updates and subscriptions. Cockpit interface can also be used to apply Policy-based Decryption rules to disks on the systems.

Virtual Machines can now be created and  managed using Cockpit. Another enhancement is that Networking page allows modification of firewall rules.

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Replacement of  nfsnobody user with nobody

nfsnobody  and nobody user of CENTOS 7 with ID of 65534 and 99 respectively have been merged as single user nobody with ID 65534 and CENTOS 8 installation no more creates nfsnobody user.

 

Databases, webservers, languages

  • Databases Servers in CENTOS 8: 

    MySQL 8.0, MariaDB 10.3, PostgreSQL 9.6 and PostgreSQL 10, Redis 4

  • Python 3 .6

     is distributed on CENTOS 8
  • Ruby 2.5
  • PHP 7.2
  • Perl 5.26
  • CENTOS 8 comes with nginx 1.14 available in the base repository
  • Redis

    : 

    The redis version available is 4.0
  • Web Servers: httpd 2.4 & 

    Nginx 1.14

    *
  • OpenLDAP replaced by 369 LDAP Server
  • Varnish Cache 6.0*
  • Git 2.17
  • Maven 3.5
  • Perl 5.26* and 5.24
  • Node.js 10* and 8*
  • Python 3.6* and 2.7*
  • Rust Toolset 1.26*
  • Scala 2.10
  • Go Toolset 1.10*
  • GCC System compiler 8.1
  • .NET Core 2.1*
  • Java 8 and Java 11
  • Pacemaker cluster resource manager 

    2.0.0

    . The pcs configuration system fully supports Corosync 3, knet, and node names.
  • glibc libraries based on version 2.28

 

Desktop 

CENTOS 8  Desktop Environment has been rebased to GNOME 3.28 that include new features like on screen keyboard, extended device support. Wayland  replaces the X.org of previous CENTOS release and is the default display server  in CENTOS 8 that offers advantages like improved multi-monitor support, enhanced UI scaling, 

  • New on-screen keyboard
  • New GNOME Boxes features
  • Extended devices support, most significantly integration for the Thunderbolt 3 interface
  • Improvements for GNOME Software, dconf-editor and GNOME Terminal
  • GNOME Software utility, which enables you to install and update applications and gnome-shell extensions.
  • GNOME Display Manager (GDM) use Wayland as their default display server instead of the X.org server

 

Features of Wayland display server

  • Stronger security model
  • Improved multi-monitor handling
  • Improved user interface (UI) scaling
  • The desktop can control window handling directly.

 

Networking

iptables has been replaced with nftables as default packet filtering framework which is the successor to  iptables, arptables, and ebtables tool.

nftables has several advantages like it offers single framework for ipv4 and ipv6 protocols packet filtering. Another utility nftrace is provided that helps in debugging and tracing in the ruleset.

TCP Networking Stack version 4.16 is distributed on CENTOS 8 that provides more stability and better performance.

By Default, firewalld uses nftables 

 

Virtualization

Bunch of new features are added like KVM supports 5-level paging, additional crash information in case KVM guest crashes, Ceph storage is now supported as well on KVM

CENTOS 8 is distributed with qemu–kvm 2.12 with new features like support for  Q35 guest machine type, UEFI guest boot, vCPU hot plug/unplug, Guest I/O threading.

 

Security

The openssh package have been upgraded to version 7.8p1 that removes support for ssh version 1 protocol, Enhancement in rsyslog is also there with upgraded rsylog version 8.37.0 

 

Containers without daemons

CENTOS 8 comes with Podman and buildah aka CRI-O that is alternative to dockers and can be used to manage containers.