CloudLinux: What You Need to Know About It
Last updated on Sep 9, 2016
If you are in the habit of reading the list of features and services being offered by different web hosts, you might have come across the name CloudLinux quite often. This is particularly true for shared web hosts and reseller hosting providers — CloudLinux is fast becoming a highly popular and well-loved operating system, especially for shared hosting environments.
However, what exactly is CloudLinux? We know that it is an operating system, a Linux distro, that caters to the needs of web hosting providers. But how is it beneficial? Does it offer anything of value for web hosts and end users alike? Why is it so popular?
This article shall answer the above questions about CloudLInux.
What is CloudLinux?
CloudLinux began in 2010, and it currently is used by thousands of web hosts. In simple terms, CloudLinux is a Linux-based operating system that lets hosts have better control over their server’s resource usage. It isolates the accounts on the server, such as the performance of one account is purely unaffected by that of another, and so on.
Naturally, CloudLinux works towards providing better granular control to web hosting providers, and offering a more stable and robust hosting environment. Among other things, CloudLinux also comes with several handy features of its own, such as a PHP Selector feature that gives end users the ability to pick the PHP version that they wish to use.
How Does it Work?
CloudLinux relies on a kernel technology named LVE, or Lightweight Virtual Environment, that offers a form of virtualization layer. Rather than entering into textbook-level terminology, let us comprehend this with the help of a simple example.
Let us assume that there are ten different user accounts on a given shared hosting server. Now, if one of these ten accounts gets a spike in traffic (say, the given website goes viral overnight), there are good chances that the resource usage of the entire server might turn unstable.
CloudLinux prevents the above scenario by offering a form of encapsulation layer for each account. In other words, each account is given its own share of CPU and memory resources, and if one account overuses the given quota of resources, it is throttled, or limited. The other accounts on the same server, however, remain unaffected.
As you might have guessed by now, this offers a very stable hosting environment and is easier to manage for web hosting providers. Furthermore, the CloudLinux file system, commonly known as CageFS, limits each user account to its own “cage”, such that any user account cannot see the data owned by a different account, and vice versa. The end users cannot see files owned by other users, nor can they access the system configuration files owned by the server admin, and nor can they execute or terminate processes managed by other accounts. As such, from a security perspective, CageFS ensures that any mishap that happens in one user account, say a malware infection, stays in that given account only.
The Advantages of CloudLinux
Quite obviously, the biggest benefit of CloudLinux is that it can ensure the stability and safety of the overall hosting server. If one user account consumes too many resources, that particular account is caged, and the other accounts are not affected. Similarly, if one user account is compromised, the infection or security threat does not spread to the other accounts on the same server.
Furthermore, CloudLinux prevents end users from seeing server configuration files and other sensitive information. This, of course, is a necessity and less of a unique feature, as any decent operating system worth its salt should ensure that system files are properly hidden from non-admin users.
All said and done, CloudLinux is definitely helpful when it comes to managing a hosting server, and hosts can keep track of resource usage easily, and making sure that everything runs smooth, stable and secure.
The Disadvantages of CloudLinux
The negative aspects of CloudLinux are rarely mentioned, as most web hosts that use it would rather bypass negative qualities of their OS, and the web hosts that do not use it have no interest in talking about CloudLinux anyway.
There are no hard and fast drawbacks of CloudLinux on paper. But in practical terms, many of its features tend to be misused and can be counted as drawbacks.
Take the case of PHP Selector. CloudLinux allows you to pick the PHP version that you wish to use, be it 5.3 or 7. However, if your web host is not proactive, there are good chances that the default PHP version is still 5.3 on your server, which has reached end of life quite a while back. Now, many users do not bother changing this (or are even unaware of this), and continue using popular scripts such as Drupal, WordPress and others whilst running PHP 5.3. This is definitely a security risk, as even though they may keep their CMS and plugins updated, the PHP version itself is obsolete and may not play well with the latest scripts.
Similarly, CloudLinux allows web hosts to monitor MySQL usage, as well as CPU, I/O and memory usage. In the hands of a poor web host, these features can make life difficult for the end user, as hosts find it convenient to monitor and throttle, as well as severely cripple the resource usage on cheaper plans so as to compel users to upgrade to costlier plans. This is why you might notice nearly all the smaller and cheaper budget web hosts relying on CloudLinux. This is, for sure, a practical consideration, as a decent web host will use the same monitoring tools to run the server well and wisely, whereas a bad host might misuse those tools to blame the users for their overcrowded and oversold servers.
At the end of the day, CloudLinux has more advantages than disadvantages. Being a premium product, it is patched and updated regularly, and since it makes the hosts’ lives easier, it is here to stay.
The drawbacks that CloudLinux has have more to do with the manner in which some web hosts use it, and less to do with the operating system in itself. The same OS in the hands of a good web host can become a tool for better hosting management.
Sufyan is a contributor to a variety of websites and blogs about technology, Linux, open source, web design, content management systems and web development. Learn more about his works on sufyanism.com