Simple shared hosting is a hosting environment in which clients receive access to a folder on a web server but cannot increase their privileges to configure any part of the operating system, web server, or database. Like a university server where you are given an account and a home folder, it is easy to get started, since the hard parts are taken care of for you. There is no need to configure Apache, PHP, or the underlying OS. In fact, you can’t change system-wide preferences even if you wanted to, since that would impact all the other users!

Simple shared hosting is very much analogous to a condominium in that resources (like the building, electricity, heat, swimming pool, cable, and power) are shared between all tenants at a lower cost than a single-family home could achieve. The condo management team takes care of cutting the grass, cleaning the common areas, and security so that clients don’t have to. However, there are sometimes restrictions on what you can do (can’t paint door red, hang laundry on patio), and many choices are made for you (like the cable provider, color of the building, and condo fees).

A shared host, like the condo, also pools resources (like CPU, RAM, bandwidth, and hard-disk space) and shares them between the tenants. It manages many aspects of the server (such as security and software updating), and restricts what tenants can do on the machine (in the name of collective good). Just like in a condo, a bad neighbor can have a severe impact on your experience since they can monopolize resources and encourage more restrictive rules to prevent their bad behavior (which also restricts you).

The disadvantages of simple shared hosting are many. Lack of control, poor performance, and security threats make shared hosting a bad idea for a serious website.

Lack of control is not a problem for a static HTML site or a default WordPress installation. However, if you want to install software on the server, most shared hosts do not permit it. That means unless the software is already installed, you must ask politely and hope they say yes (they normally say no). This inability to install software can also manifest as a missing service such as no SSH access (remote command-line access) to the server or no git (version control) client. Moreover, you cannot use a particular version of some software, but rather must use what is installed for everybody. The choices that are good enough for the majority can often be too constraining for a custom website. Lack of control can also limit what’s possible to do with your site. For example, if you use a shared IP address, then you cannot create a reverse DNS entry to validate that the IP address is really yours, since it actually belongs to hundreds or thousands of sites that are being hosted on the same server.

Poor performance is a more common problem with shared hosts. Although a good web server can easily support dozens or maybe a few hundred sites that are not too busy, some shared hosts serve thousands of sites from a single machine in the hopes of making a larger profit. Sometimes an intense script running in another domain on the server can impact the availability of CPU, RAM, and bandwidth for your site.

Security threats are not uniform across all hosts. The vulnerabilities of one host may not be present on another, but scanning your host for vulnerabilities could be considered a threat and may even be illegal. If security is a concern, simple shared hosting should be avoided.

Virtualized shared hosting is a variation on the shared hosting scheme, where instead of being given a username and a home directory on a shared server, you are given a virtual server, with root access as shown in Figure 17.11.

Figure 17.11 Virtualized shared host, where each user has a virtual server of their own

When a single physical machine is partitioned so that several operating systems can run on it simultaneously, we call each operating system a virtual server, which can be configured and controlled as the super-user (root).

Virtualized hosting mitigates many of the disadvantages of simple shared hosting while maintaining a relatively low cost. Although there are still some restrictions, there are far fewer of them. Since the server is virtual, you are usually given the freedom to install and configure every aspect of it. Virtualization is also the means by which cloud hosting providers provide scalable hosting packages, and how modern DevOps workflows work. (For more detail on server virtualization, look ahead to section 17.3.)

The authors recommend this configuration over simple shared hosting for most web developers for its relatively low cost, its ability to easily host more domains for free, and its additional flexibility and security.

The obvious alternative to collocated hosting is to manage the web server yourself, entirely in-house. This provides some of the advantages in terms of control but has major disadvantages since you must in essence manage your own data center, which introduces all types of requirements that you may not have yet considered, and that are difficult to justify without economies of scale that data centers enjoy.

Although hosting a site from your basement or attic may seem appealing at first, you should be aware that the quality of home Internet connections is lower than the connections used by data centers, meaning your site may be less responsive, despite the computing power of a dedicated server.

Ideally, an in-house data center is housed in a secure, climate-controlled environment, with redundant power and network connectivity as well as fire detection and suppression systems. In practice, though, many small companies’ in-house data centers are just closets with an air conditioner, unsecured, and without any redundancies. The savings of hosting everything in-house can easily evaporate the moment there is an outage of power, Internet connectivity, or both.

All that being said, many companies do use a low-cost, in-house hosting environment for development, preproduction, and sandbox environments. Just be aware that those systems are not as critical as a production server, and therefore have a lower need for the redundancy provided by a data center.