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CloudLinux on a VPS: when you need it and what the licence costs
CloudLinux is a commercial system for servers that host many other people's sites: it is package-compatible with RHEL and AlmaLinux, but adds mechanisms that stop a single account from taking down the whole server. It is used by people who resell hosting themselves, run a server for a web agency's clients or host dozens of sites belonging to different owners. If your VPS runs a single project of your own, CloudLinux gives you almost nothing, and plain AlmaLinux is enough.
What CloudLinux does on a shared server
- LVE sets limits for each user: CPU share, memory, disk speed and number of I/O operations, number of processes and concurrent incoming requests. A site that comes under load or gets stuck in a loop hits its own limit, while its neighbours keep working.
- CageFS gives each user their own virtual file system. One account's scripts can't see other people's files, other users or most system utilities.
- PHP version selection for each account separately, including old branches that PHP itself no longer supports: the CloudLinux developer releases fixes for them.
- MySQL load limits per user, so that heavy queries from one site don't slow down everyone else's databases.
All of this is managed from a control panel: CloudLinux works together with cPanel, Plesk and DirectAdmin, and is used far less often without a panel.
The licence: the main expense
CloudLinux is paid software, and the licence is usually not included in the VPS price shown in the table. You buy it monthly from the host (if they resell it), from a panel licence reseller or directly from the developer. Licences are tied either to the server's IP address or to an activation key; if you move to a new VPS with an IP-bound licence, it will have to be reissued. There are several editions: one for shared hosting with many users, an extended one with extra site acceleration features, and simplified ones for a server with a single owner. Before ordering, add up the total: the VPS price, the panel licence and the CloudLinux licence. On small plans the licences often cost more than the server itself.
Also check what "CloudLinux" means in a particular host's OS list: a ready template with an activated licence, a template without a licence, or simply the option to install the system yourself. In the table these cases look the same, but the price difference can be noticeable.
How to install it and on what
LVE works at kernel level, so CloudLinux needs a VPS with full virtualisation, ideally KVM. On OpenVZ and LXC containers the kernel is shared by all of the host's customers, and CloudLinux won't install there. If there is no ready image, you get the system by conversion: install AlmaLinux or Rocky Linux of the same major version, then run the official conversion script with your licence key and reboot into the CloudLinux kernel. With cPanel the order is usually the reverse: conversion first, then the panel, although converting a running cPanel server is also supported.
Before converting a server that already hosts sites, take a disk snapshot in your host's panel. After the reboot, check that the right kernel is loaded and enable CageFS for all users: by default it isn't enabled for everyone.
What resources to choose
The system itself uses no more than ordinary AlmaLinux, but on a shared server resources are split between accounts, and you need headroom from day one. Guidelines for a server with cPanel and CloudLinux:
- up to 20–30 small sites: from 4 cores, 8 GB of memory and an NVMe disk of 100 GB or more;
- a hundred accounts or more: from 8 cores and 16–32 GB of memory; at this point it's worth comparing the price with a dedicated server;
- disk: SSD or NVMe only, since I/O limits are pointless if everyone shares one slow disk.
Set LVE limits for your hosting packages before moving clients over: if you set them too low on a live server, sites will start returning error 508 and their owners will come to support. To begin with, it's sensible to take the panel's default limits and watch the limit-breach statistics for a week.
And don't forget backups: CloudLinux isolates accounts but doesn't protect data. Keep copies of sites and databases outside the VPS itself, on a separate server or in object storage, and once a month test restoring at least one account. Install kernel updates on a shared server during a maintenance window announced to clients in advance: a reboot affects everyone at once.