What is CloudLinux?

CloudLinux is a hosting-oriented Linux distributive based on CentOS. It uses LVE (Lightweight virtual environment) kernel technology that is similar to OpenVZ in some aspects or other OS-based virtualization technologies.

In shared hosting the most common downtime reason is a single account grabbing most of shared resources due to heavy site(-s) or unoptimized script(-s). CloudLinux OS is designed especially for servers being used in this way, making the situation when one or several users severely load or even hung up the server impossible.

CloudLinux improves the server stability by encapsulating each client in a secure, isolated environment. It means that each user on the server is limited by the amount of resources it can use, being placed in so called “container” (separated operating environment).

The following diagram demonstrates the work of the Traditional server environment vs. CloudLinux:

Additionally, CloudLinux includes CageFS – a virtualized file system, a set of tools to contain each user in its own ‘cage’. Each customer has its own fully functional CageFS, with all the system files, tools, etc.

The benefits of CageFS:

1. Only safe binaries are available to user;
2. User will not see any other users, and would have no way to detect presence of other users & their user names on the server;
3. User will not be able to see server configuration files, such as Apache config ones;
4. Users will have limited view of /proc file system, and will not be able to see other’ users processes.

CageFS will also cage any scripts execution so in case any executable malware is opened in a different cPanel account, it will not reach the other ones in any way.

The benefits of CloudLinux:

Isolates the users from each other to avoid “neighbor effect”.
Prevents users from seeing configuration files or any other private information.
Allows to monitor and control limits, such as CPU, RAM and I/O usage.
Monitors and operates MySQL usage.
Provides CageFS file system, that uniquely encapsulates each customer.
Allows end users to select PHP versions 5.2-5.6.
Prevents symbolic links attacks compatible with all major control panel.