CentOS 7 – An Enterprise Ready Problemless OS

Introduction

It must be about 8 years now since we choose CentOS as our default operating system for Linux servers. A lot has changed since then and it has always been on my to do to write a blog post about it. Karanbir Singh announced the release of CentOS 7.4.1708 on 13/09/17. As with all CentOS 7 components, this release was built from sources hosted at git.centos.org. It also supersedes all previously released content for CentOS Linux 7, and users are highly encouraged to upgrade all systems running CentOS 7. Make sure to read the release notes before upgrading.

One month later, we were able to patch all our CentOS 7 systems and did not run into a single upgrade problem. I would say that merits a big congratulations to the whole CentOS team, and of course also all Red Hat engineers for producing a problemless and stable distribution.

In this post I’ll try to give a general overview of what CentOS is about and why you should choose for this partcular operating system.

centos 7

CentOS Lifecycle

It’s very important to keep an eye on the lifecycles of the operating systems you are managing. Good planning ensures you have enough time to migrate your applications in time before your operating systems are no longer supported. 

CentOS VersionRelease DateFull UpdatesMaintenance Updates
319 March 200420 July 200631 October 2010
49 March 200531 March 200929 February 2012
512 April 200731 January 201431 March 2017
610 July 201110 May 201730 November 2020
77 July 2014Q4 202030 June 2024

Source: https://en.wikipedia.org/wiki/CentOS 

CentOS 7 Repositories

There are three primary CentOS repositories (also known as channels), containing software packages that make up the main CentOS distribution. 

  • base – Contains packages that form CentOS point releases, and gets updated when the actual point release is formally made available in form of ISO images.
  • updates – Contains packages that serve as security, bugfix or enhancement updates, issued between the regular update sets for point releases. 

  • extras – Provides additional packages that may be useful.

  • centosplus – Provides additional packages that extend functionality of existing packages. Please note that this repository is disabled by default. Using this repository is more dangerous than using other CentOS repositories, as it is designed to have several updated packages and it is not really designed to be completely enabled. You should only pick the packages you are looking for and use exclude= and includepkgs= (or exclude= and yum-plugin-priorities) to load only those packages from the centosplus repository. (also check the official centosplus documentation)

CentOS vs Red Hat Enterprise Linux

While CentOS is derived from the Red Hat Enterprise Linux codebase, CentOS and Red Hat Enterprise Linux are distinguished by divergent build environments, QA processes, and, in some editions, different kernels and other open source components. For this reason, the CentOS binaries are not the same as the Red Hat Enterprise Linux binaries. Red Hat Enterprise Linux (RHEL) is actually also open source. But although the code is available for Red Hat users, it is not free to use. Red Hat and the CentOS project announced 7 January 2014 they were actually joining forces.

 CentOSRHEL
License FOSS – GPL and othersCommercial – RedHat EULA
SecuritySELinux, NSS, Linux PAM, firewalld SELinux, NSS, Linux PAM, firewalld
Patches/fixesAs promptly as possible given available project resources.SLA through Red Hat
SupportSelf-support24x7 support through Red Hat
Package managementYumYum
Enterprise package managementSpacewalk / KatelloRed Hat Satellite
ClusteringLinux-HARed Hat Cluster Suite (RHCS)
BootloaderGRUB 2GRUB 2
Graphical user interface (GUI)GNOME 3 / KDE SC 4.10GNOME 3 / KDE SC 4.10
Service managementsystemdsystemd
Storage managementLVM / SSM LVM / SSM
Default file systemXFSXFS
ContainerizationDocker, KubernetesRed Hat OpenShift
Virtual device interface (VDI)SPICESPICE

red hat

There are a lot of advantages in choosing Red Hat 7 over CentOS 7. 

  • Enterprise-level support
  • Access to engineering resources
  • Red Hat’s Customer Portal
  • Certifications
  • Latest features

But choosing Red hat also has some considerable disadvantages:

  • Not free
  • Administration overhead for license management

And yes, I do mention the administration overhead as a problem. This problem might not apply for everyone though. In my case though the process of ordering new Red Hat licenses or prolonging expiring licenses just takes a lot of (unnecessary) time. 

Final words

So I hope my blog post gave you some additional information to make a better informed decision which operating systems are best suited for your use case. If you need professional support, Red Hat is there for you, if you feel comfortable supporting your own Linux servers, follow the CentOS rabbit.