CentOS vs Ubuntu

There are hundreds, maybe thousands, of flavours of Linux ("distributions"). But on servers only two dominate: CentOS and Ubuntu. So, which is better for serving websites and web apps?

Summary

The logos for CentOS and Ubuntu

  • CentOS is based on Red Hat Linux Enterprise, Ubuntu is based on Debian.
  • CentOS uses .rpm packages and the yum package manager, while Ubuntu uses .deb packages and the apt-get package manager.
  • Ubuntu is more frequently updated than CentOS, so you get the latest package updates sooner.
  • CentOS offers the longest support period, up to 10 years.
  • Ubuntu has better documentation and a more active community, but there's good commercial support available for CentOS.
  • CentOS supports cPanel, Ubuntu doesn't. Apart from that, Ubuntu is considered easier to use for non-sysadmins.

Origins

CentOS and Ubuntu have their origins in entirely different Linux distros. Ubuntu is based on the venerable Debian distribution, while CentOS – which stands for Community ENTerprise Operating System – is basically a free version of Red Hat Enterprise Linux (RHEL), a commercial product. The CentOS team is a volunteer group that rebuilds publicly available RHEL sources. Nowadays, CentOS is officially supported by Red Hat, too.

The main difference in terms of the user experience is found in their package management systems. CentOS uses RPM packages installed via the yum package manager, while Ubuntu uses DEB packages managed by apt. The package managers offer much the same functionality, but their commands are entirely different. If you have experience of other Debian-based distros, you will likely feel more at home with Ubuntu's package management system. Likewise, if you have experience of RHEL, you will feel right at home with CentOS.

Users of the Ubuntu desktop OS will naturally be drawn to the Ubuntu brand. But GUI and CLI environments are very different beasts. There are no productivity gains to be had from choosing a headless version of a familiar desktop distro.

Community

Ubuntu has a large, active community. Thousands of users from all of the world hangout in various online forums and groups and dole out expert advice for free. There are lots of tutorials, videos, courses, books and more, both free and commercial, for Ubuntu.

CentOS, though free, is considered a commercial product and so has a less active community and a much smaller volume of free support material. On the other hand, there is good commercial support available for CentOS. You can more readily find SysAdmin and DevOps engineers with expert knowledge of CentOS.

Release cycle

Like RHEL, CentOS is very conservative in terms of upgrade cycles. CentOS has far less frequent updates, and tends to focus on security patches and maintaining stability and consistency for long periods of time. By comparison, Ubuntu tends to ship with much fresher packages, and updates tend to land in the Ubuntu repos before they turn up in CentOS. Ubuntu also offers a much more diverse and extensive range of packages, and has excellent support for cloud and container deployments.

As well as longer release cycles, CentOS also provides much longer long-term-support (LTS). Ubuntu releases an LTS edition every two years and the support lasts for five years. The gaps between CentOS LTS editions are even longer, but so is the lifespan of the support: up to 10 years. CentOS 6 was first released in 2010 and will continue to be supported up to 2020.

Security

Due to its less frequent updates and the longer support periods, CentOS is considered to be more stable and secure. Updates are tested for longer periods of time prior to their distribution. Buggy releases of applications are less likely to get added to the official CentOS package repositories.

Also, CentOS makes use of the SELinux framework for hardening the security layer.

A well-known philosophical difference between CentOS and Ubuntu is that Ubuntu disables the root account, such that no administrator knows the root password (which is randomly generated). Root privileges are granted exclusively through the sudo command. Of course, root access can be manually disabled on CentOS, but on Ubuntu this is the default configuration. This may be an attractive feature in organisations where systems are managed by devs rather than ops.

Server GUIs

Most web server GUIs – including InterWorx and the most popular one, cPanel – support only RHEL and its derivatives, such as CentOS. For this reason, CentOS is preferred over Ubuntu by web hosting companies and web design agencies.

Performance

Overall, Ubuntu is a lot heavier than CentOS, being shipped with a much more extensive suite of features. That said, there is little discernible difference in performance between CentOS and Ubuntu. The speed of your web server will be determined by its configuration and the underlying hardware.

Conclusion

In general, choose CentOS for commercial products, Ubuntu for personal websites and pet projects. In practice, you may have more specific and nuanced requirements that will dictate the optimum distribution.

The main consideration is the trade-off between consistency and stability on the one hand, and getting easy access to the very latest software updates on the other. Choose CentOS if you want to keep your server infrastructure stable for as long as possible and if security takes precedence over all other considerations. If you need or crave the latest bells and whistles, you still have the option of installing things manually from source.

For this reason alone, the default choice should be CentOS. But Ubuntu is increasingly popular, especially for servers that are provisioned for specific applications, as opposed to generic web hosting services.

It is good to have experience of both CentOS and Ubuntu, so you have a feeling for how they differ in terms of user experience. You can install them in a local VM, or get a cheap VPS from Linode, DigitalOcean or Vultr. But in the long term it is better to become a master of one distribution. Ubuntu and CentOS, and other distributions, put things in different places and handle some subsystems in different ways. There are enough differences to frequently trip you up if you regularly flip from one distro to the other.