Debian is over 20-years-old and in part owes that longevity to the emphasis placed on producing a stable operating system. This is crucial if you want to set up a server as updates can sometimes clash badly with existing software.
There are three branches of Debian, named 'Unstable', 'Testing' and 'Stable'. To become part of the Stable current release, packages must have been reviewed for several months as part of the Testing release. This results in a much more reliable system – but don't expect Debian to incorporate much 'bleeding edge' software as a result.
You can get started with Debian using a minimal Network Boot image which is less than 30MB in size. For a faster setup, download the larger network installer which at just under 300MB contains more packages.
2. Ubuntu Server
While Ubuntu is best known for bringing desktop Linux to the masses, its Server variant is also extremely competitive. Canonical, the company behind Ubuntu, has developed LTS (Long Term Support) versions of Ubuntu Server, which like the desktop flavour can be updated up to five years after the date of release, saving you the trouble of upgrading your server repeatedly. Canonical also periodically releases versions of Ubuntu Server at the same time as the latest desktop distro (i.e. 18.04).
If you're intent on building your own cloud platform, you can also download Ubuntu Cloud Server. Canonical claims that over 55% of OpenStack clouds already run on Ubuntu. For a fee, Canonical will even set up a managed cloud for you using BootStack.
OpenSUSE (formerly SUSE Linux) is a Linux distro specifically designed for developers and system admins wishing to run their own server. The easy-to-use installer can be configured to use 'Text Mode' rather than install a desktop environment to get your server up and running.
OpenSUSE will automatically download the minimum required packages for you, meaning only essential software is installed. The YaST Control Center allows you to configure network settings, such as setting up a static IP for your server. You can also use the built in Zypper package manager to download and install essential server software such as postfix.
4. Fedora Server
Fedora is a community developed operating system based on the commercial Linux distro Red Hat. Fedora Server is a special implementation of the OS, allowing you to deploy and manage your server using the Rolekit tool. The operating system also includes a powerful PostgreSQL Database Server.
Fedora Server also includes FreeIPA, enabling you to manage authentication credentials, access control information and perform auditing from one central location.
You can download the full 2.3GB ISO image of Fedora Server using the link below. The same page contains a link to a minimal 511MB NetInstall Image from Fedora's Other Downloads section for a faster barebones setup.
Like Fedora, CentOS is a community developed distribution of Linux, originally based on the commercial OS Red Hat Enterprise Linux. In light of this, the developers behind CentOS 7 have promised to provide full updates for the OS until the end of 2020, with maintenance updates until the end of June 2024 – which should save the trouble of performing a full upgrade on your server in the near future.
You can avoid unnecessary packages by installing the 'minimal' ISO from the CentOS website, which at 792MB can fit onto a 90 minute CD-R. If you're eager to get started, the site also offers preconfigured AWS instances and Docker images.