Ubuntu is a really popular OS, that uses the Linux kernel. Although it is used primarily on PCs, its server version has been becoming more popular nowadays as well. Ubuntu is one of the lightest Linux distributions available and it's compatible with almost any hardware, that makes it a universal OS. In addition, it is very stable and secure and has an no less than a five-year support life cycle, so you will be able to receive official security and performance updates. Unlike numerous other Operating Systems, Ubuntu is distributed without any license fees and you're able to modify its core, or any of the thousands of packages it comes with, in any way you find fit. This will allow you to set up the proper software environment for all of your web applications whatever their specifications. Due to the popularity of the OS, Ubuntu has large developer and user communities, which means that you will always find plenty of materials online about any question or problem that you might have.