Posted on 09/25/2014 8:14:50 AM PDT by ShadowAce
Credit: Thinkstock
Unlike most other desktop and server operating systems, Linux comes in a wide variety of flavors, each based on a common core of the Linux kernel and various GNU user space utilities. If you're running Linux servers -- or Linux desktops, for that matter -- you should understand the important differences and be discerning about which flavor of Linux is best suited to any given situation. This article will help you do just that.
Because Linux is open source software, the number of discrete Linux distributions is hard to know for sure. But a short list of major distributions account for the lion’s share of commercial Linux deployments: Red Hat Enterprise Linux (RHEL), CentOS, Fedora, Ubuntu, Debian, and OpenSuse.
Even so, there are clear delineations among them, mostly in the area of system design. When it comes to managing Linux in a production environment, you will find important differences in everything from stability to support for popular open source packages. Failing to appreciate these nuances can mean the difference between smooth sailing and choppy waters when it comes to deploying and running your application.
Take the Web server, for example. All Linux distributions bundle the Apache Web server, but each implements Apache using slightly different file system layouts and configuration conventions.
For instance, Ubuntu calls Apache version 2 "apache2", while CentOS and RHEL call it "httpd". That affects where configuration files for Apache are located within each distribution. You can find them in …/etc/httpd on CentOS and Red Hat, but …/etc/apache2 in Ubuntu. Furthermore, Ubuntu and similar distributions might place the Apache document root in …/var/www, while CentOS and RHEL opt to put it in …/var/www/html.
Further, Ubuntu offers a homegrown Apache configuration management scheme that allows an admin to place Apache configuration snippets in /etc/apache2/sites-available and /etc/apache2/sites-enabled, and manage them with custom commands such as a2ensite and a2dissite that move those snippets around and reload Apache. This means you can enable and disable virtual websites from the command line. CentOS/RHEL don’t have anything like this, requiring manual management of the configuration files.
Ubuntu’s approach isn’t necessarily better or worse -- it’s a matter of personal preference. On one hand, it does make operations like setting up a website easier. On the other hand, you need to prepare your configurations in such a way to work with customized configuration commands. Purist Apache admins would probably simply work with the files directly. Newer users may find Ubuntu’s approach helpful. Ultimately, it’s up to you to decide which is preferable.
There are other differences. By default, Ubuntu locks down the root user, instead requiring that a local user be created during installation; that user is then granted sudo privileges in order to perform tasks as the root user. CentOS/RHEL have no such restriction and allow for general access by the root user.
Some distributions also have customized configuration tools. Suse Linux (and OpenSuse) sport YaST (Yet another Setup Tool), a system setup and configuration manager that isn’t used in other Linux distributions.
In other cases, there may be broad similarities among current distributions that aren’t shared by older versions. For example, systemd has been introduced as a replacement for sysvinit in recent releases of the major Linux distributions, fundamentally changing the way servers running these distributions boot, load, and manage services (and not without controversy). Older releases of these distributions will not have systemd, and thus will not benefit from the greater efficiency and performance improvements that it brings. That may be a factor worth considering if you’re presented with a choice of release versions.
Another key element that differentiates Linux distributions is the package update mechanism and the frequency of package updates. On Ubuntu and Debian, you use Apt (Advanced Package Tool) to handle distribution updates. This tool allows you to update individual packages or the system as a whole. On RHEL, CentOS, Fedora, and others, Yum (Yellowdog Updater, Modified) is the package manager. Apt and Yum operate in similar ways, letting admins configure custom package repositories, and easily upgrade packages and maintain the system.
Generally speaking, the major Linux distributions align as described in the table below.
Major Linux distros at a glance |
|
| RHEL and CentOS | Stable, older kernel and base packages. There is a long release cycle, and “current” packages based on two-year-old releases are common. Arguably the most deployed Linux distribution. A favorite of Linux veterans. |
| Fedora | Less stable, but much more frequent kernel and package updates. Can be considered the testing distribution for RHEL/CentOS. |
| Ubuntu | A mixture of stable, older releases with current maintenance, and less stable, much more up-to-date revisions. The LTS releases are the ones to watch for stability and long-term support. May be easier for novices. |
| Debian | Ubuntu is based on Debian, and you’ll still find some similarities between the two. Debian functions with three concurrent releases: "stable," "testing," and "unstable." Production workloads should be using "stable," and that release cycle can be quite long. |
| OpenSuse | Although distantly related to Red Hat, OpenSuse is quite different from all other Linux distributions. It relies on the YaST configuration tool, and while a capable distro, has been marred by the involvement of Novell and Microsoft. |
The choice of which distribution to use typically reduces to a few key elements:
Familiarity. The advantages of sticking with a Linux distribution you’re extremely familiar with will generally outweigh the advantages of adopting a different distribution. If CentOS and RHEL are what you know, sticking with these distributions will likely be easiest in the long run. Unless server requirements dictate otherwise, go with what you know.
Simplicity. There is a lot to be said for homogeneity in application stacks. Maintaining the same distribution across your stack is almost always the way to proceed. If your application servers run CentOS, then your database servers should too, unless there is an overriding reason to go a different direction for those servers.
Server requirements. Ultimately, your choice of distro will be limited by the applications and services you need to deploy. For example, if the server must run the very latest releases of a common package like MySQL or PHP, choosing a stabler distribution like CentOS or RHEL with a longer release schedule will complicate matters. You will likely need to resort to additional, third-party package repositories and use packages built by a variety of contributors rather than the official releases supported by the distribution. In some cases, you may have to create your own package RPMs or custom package compilations for very recent package releases.
Alternatively, a little research may show that Fedora already has the version of MySQL or PHP you need, so using Fedora will save you valuable time and effort. In other cases, Ubuntu or Debian might more closely match the software requirements of your server, and thus will be worth considering even if you are not as familiar with them.
You may also find that your planned application or service stack comes with suggestions or recommendations on which distribution is a best fit. In addition, you could find some solutions have prebuilt packages for a few Linux distributions. Your best bet will be to stick with those versions to ensure compatibility.
Stability. Finally, it pays to be conservative. Relying on stable OS releases should always be the default approach. If a stable version doesn't meet the server software requirements, then moving out to a more recent release may make more sense than adapting the older, more stable release with more recent packages.
Rarely should a production server be run on unstable or testing releases from any vendor. Some administrators interpret this guidance to mean that Fedora and non-LTS versions of Ubuntu should never be run on production servers. While that is a good rule in general, there are always exceptions. Understand the risks involved, and be prepared to encounter the hidden issues that usually crop up when dealing with unstable or testing releases.
In many cases, the choice of Linux distro isn't entirely up to you. If you're shopping for a VPS (virtual private server) or cloud server instance, or even for a dedicated server at a hosting facility, you will find that providers offer a limited set of supported distributions to choose from. For the vast majority of those providers, those supported distros will be a subset of RHEL, CentOS, Fedora, Ubuntu, Debian, and OpenSuse.
It’s not uncommon to find providers that offer only CentOS and Ubuntu, or perhaps those distros along with Fedora and Debian. Fewer will offer OpenSuse, so predominately the choice comes down to these four or five distributions. The guidelines above, and the table below, should help you figure out which is best for your project.
Of course, your best course is to get comfortable with as many different Linux distros as you can, so you're prepared to use each when its strengths are a match for the job at hand.
Major Linux distros compared |
||||
| Pros | Cons | Package management | Versions | |
| RHEL and CentOS | Very stable and reliable; very well supported; used almost everywhere; very traditional layout and management approach | Very long release cycle; packages will be older and generally more difficult to bring to current if required | Yum and RPM; can use third-party repositories | Versions 5 and 6 still supported, 7 just released |
| Fedora | Quite cutting-edge – sometimes bleeding-edge; lots of supported software with recent releases | Can be less than stable due to fast-paced package and release updates; generally thought to be Red Hat’s testing distribution | Yum and RPM; can use third-party repositories | Versions 19 and 20 still supported, 21 set for release late 2014 |
| Ubuntu | Solid release cycle based on LTS (Long Term Support) and intermediate releases; user friendly, with lots of “helper” commands | Tends to move quickly and packages can be less stable than others; has unique conventions that don’t translate to other distributions | Apt and Deb packages | 10.04 LTS, 12.04 LTS, and 14.04 LTS all currently supported |
| Debian | Very stable and reliable; wide variety of support packages; all-volunteer maintainers; supports large variety of architectures | Very conservative; release cycle can be slow | Apt and Deb packages | Stable: wheezy; testing: jessie; unstable: sid |
| openSUSE | Stable, solid distribution; plenty of support packages; has sys admin tools such as YaST | Has been stunted by Novell’s acquisition and dealings with Microsoft that assume rights over portions of Linux; has unique sys admin tools such as YaST | YaST and RPM | Versions 12.3 and 13.1 supported, 13.2 set for release late 2014 |
Older Computer/Laptop go with Lubuntu 14.04 ,it’s like Windows XP ,install it and use it ,Da Da
Debian Testing is working out fine for me... home use.
The base system is pretty solid (no crashes) and the apps are updated very frequently.
I use the XFCE desktop—simple, fast.
even my 80 year old mother uses Lubuntu
XFCE is my favorite. I use Fedora, but I’ve always been a Red Hat guy.
I used Fedora for years, but of late, the changes in the six-month cycle have been disconcerting. Maybe two years ago, I had Fedora 18, and liked it a lot... then when I switched to 19, there were so many loose ends and reconfigurations required that I decided to look elsewhere.
I totally understand that viewpoint. If you thought 19 was bad, wait until 21 comes out. LOL!
I like my Ubuntu 12 point something LTS.... I’ll stick with it for a while probably
For someone that doesn’t want to use his old XP computer and won’t be using it, but does want to get on it only to google for computer answers, and to download a free security program to repair his real computer, what is the simplest, easiest OS for that?
I put Cinnamon on one, and don’t like it, is there a simpler, easier to understand OS that is still secure enough for this simple task?
Distrowatch dot com has Mint over ubuntu (Mint first place) by a substantial margin.
Mint escapes mention here, though I understand it is a variant of Ubuntu, it is a rather distinct fork.
Uh, I already know about the list.
Never mind.
Anybody running a linux version on a chromebook?
I use Mint on an HP laptop to do ruby and Java programming. I use eclipse for an IDE occasionally but mostly prefer vi because it’s extremely fast. I have used various distributions since 1998... Mint is as good as anything IMHO. We use RHEL for server instances and prefer them in production.
Though my company is a Windows shop, we’ve got some Linux, mostly desktops, but a few servers, mostly running Zimbra as our corporate mail system. We used to be standardized on SLES, but have since moved to Centos for the desktops (I had nothing to do with it, and don’t work on them), and we’re now moving to Ubuntu on VMs for the ZImbra. I’ve liked Ubuntu for a while now.
But I haven’t really done any SERIOUS *IX since about 1989, so I’m really rusty at it, and google is my friend.
Mark
I’ve used Suse since version 8.0, mandrake before that.
Still dual boot, but usually go months without using windows.
Played with debian for awhile just for fun, but that really didn’t see the need for it.
Guess I’ll just stick to opensuse with KDE desktop because I am old and really not too interested in learning anything new.
A few years ago the Mint developer (Lefebvre?) asked those who supported Israel not to use Mint.
He caught some flack for that, and I ignored him.
My eyebrows shot up when I read your post, and I had to question its validity. However, a brief ixquick search turned up this:
“Support Israel’s Government? Linux Mint Developer Says Go Away”
http://abriefhistory.org/?p=774
Yes, I think he took some flack for that, and rightly so.
I raised my eyebrows when I read of it when it was current news.
There was (and is) a group of Euro intellectuals who want peer review, article submissions, etc., to exclude Israelis. He probably “me too’d” that movement, which is still kicking in some “smart” quarters — including The Lancet.
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