CentOS 6 Linux, A First Look

I've been running CentOS 5.x for a number of years, mostly on servers, and have been extremely happy with it. In fact, I've upgraded servers along the way, up to 5.6 and have also been amazed at the seamless upgrade process from version to version. For those that don't know, CentOS is the free derivative of Red Hat Enterprise Linux. The source is compiled and released as its own distribution that is so close to Red Hat Enterprise that packages can even be interchanged between the two. I have to tip my hat at the developers that release CentOS, they do a ton of work and the documentation on the CentOS Wiki site is excellent.

This past weekend I finally got a look at CentOS 6, which every CentOS user has been anxiously waiting for since Red Hat announced RHEL 6 a while back. I'm a little late to the game, but unfortunately time has prohibited from checking it out sooner.

At first glance, I have been very pleased at what I've found with CentOS 6. It is clearly a hardened OS, based on the legendary Red Hat Enterprise Linux that is well known among large and small businesses. Since CentOS doesn't include the latest cutting edge software, it continues to be one of the most stable GNU/Linux distributions, which also includes an excellent and long lifecycle. In general as published on the CentOS Download page, feature enhancements and new hardware support lasts up to 4 years after the release date for a version of CentOS, and security fixes for up to 7 years. This is what makes CentOS so appealing especially on servers which don't need the cutting edge versions, but can have stability and a long lifecycle of the version installed. CentOS 6 will be updated until November of 2017.

So what's new in CentOS 6? If you have used previous versions of CentOS, you will see many of the same things as before but just a newer set of packages. Some things have changed though, which follow Red Hat's roadmap for RHEL 6. One of the biggest features added is ext4 filesystem support, even though this was also added in CentOS 5.6 as well. The full list can be found within the CentOS 6 release notes. I noticed that CentOS 6 more closely resembles Fedora 12 or so, based on the various utilities and interfaces it comes with. It comes with a stock 2.6.32 kernel, and Gnome is at version 2.28.

One thing that threw me the first time I installed CentOS 6 is the number of choices for the type of machine you are trying to install. You are now given a number of choices which will try to select the packages to install for you. However, I found it to be a little misleading in my case because I wanted the Gnome Desktop Environment. By default, if you select for example "Basic Server", the Gnome Desktop Environment is left out. I ended up selecting "Basic Server", then checked the box at the bottom to customize the packages. Then, I added what additional services I wanted in the various package categories, and for the Gnome Desktop Environment, under "Desktops" you MUST select the following:

- Desktop
- General Purpose Desktop
- X Window System

I also added "Fonts" and "Graphical Admin Tools", but those aren't necessary. But the point is, if you don't select those three above, you will be missing some components for the full Gnome Desktop Environment. I often get asked why I would want the Gnome Desktop Environment, and the answer is that I like the GUI admin tools that Red Hat provides, including the "Samba" administration tool. The system can boot to runlevel 3 (text command prompt) and you can start X11 as desired (with the "startx" command) and shut it down by using "Logoff", so X11 and Gnome don't need to run all of the time but only when you need them. In my case, I end up using VNC to connect to the CentOS 6 server, and in GNU/Linux VNC can communicate directly with X11 so that the console can still be at a text logon prompt while I'm connected to my own private VNC session with the full desktop. This is one thing that I really like over the Windows version of VNC. I also followed an example of the excellent CentOS documentation to set up VNC on the server, with the VNC setup guide.

But, to my surprise, Red Hat with RHEL 6 (which affects CentOS 6), has decided to discontinue some of the GUI tools. The Samba administration tool is gone which I used on a regular basis. Here is a list of changes in RHEL6/CentOS6 that better outlines the tools that have been discontinued. I am a little disappointed to see Red Hat drop some of these.

But, overall I can see that CentOS 6 is going to be a very solid release and will be interesting to see where it pops up. Again, great stuff here, but most useful for server systems. There is an option for "Development Workstation" during the installation which would be interesting, but for now I'm sticking to Fedora on my desktops to ensure I get the very newest versions of everything.