How does shared web hosting work?
 

Hi,
I'm trying to understand how shared web hosting services work.

Apache virtual host seems to provide a way doing it. Is that what commercial shared web hosting services do?

When you get one of these commercial services, it allows you to add new users, install software etc. It almost seems like a scaled down version of a GNU/Linux box on a larger server. How is it being done?

I have Slackware 13.0 running Apache and was wondering if I can play around with some of these types of services locally.

Thanks in advance,

Ash.

Well, large server farms tend to use some of the latest ideas to share loads. Everything from distributed storage to virtual machines and host headers share resources. Basically almost any way to share hardware is being looked at and used. What you buy in the lower costs are virtual in nature. Almost nothing about it is dedicated. On larger packages you may actually qualify for a single system. They tend to buy systems that can support many common customers on one real system.

As for the OS it is up to the company. MS and Linux are big players along with the BSD's and Solaris. Might depend on how they price and need to support customers as to the OS choices.

Since I have an Apache running, is it possible for me to emulate some of the virtual setups?

E.g. I can setup a few virtual hosts to emulate web hosting shares, but I wasn't sure how to allow these shares to add users to their shares.

Also what are these web hosting control panels (e.g. cPanel, plesk etc.) that are provided? Do they invoke some shell command behind the scenes? Are there any free ones that I can install and play around with?

Thanks,

Ash.

actually with cpanel you start with a bare minimum system and it handles installing the rest, if i'm not mistaken it's a whole software suite that handles server clustering, database management, user management, ftp accounts, email accoungs shell accounts etc.. in addition to web hosting in short a general hosting control panel/management system
as for free?
do a google search for
open source hosting control panel
it turns up quite a few hits

There are many types of shared hosting available today. Traditional shared hosting would just be using Apache Vhosts or similar. If your users wanted email too, you would need to setup the equivalent of a vhost too.

It sounds like you are using some sort of virtual server based shared hosting, where you have root access to your virtual machine. I imagine you could create Apache virtual hosts.

It isn't very clear what you mean by creating shares and adding users. What 'users' do you want them to be able to create?

I have never used cPanel, but I am quite familiar with Plesk. The Plesk control panel is essentially a web based control panel, oriented to the creating and managing virtual hosting (setting up apache vhosts, creating email accounts, configuring server settings etc.). Fundamental to the operation of Plesk is it's hierarchical account and security system. There are (I think) six heirarchical levels of user in Plesk:

• Admin (root essentially)
• Reseller
• Client
• Domain
• Sub-domain (this is optional)
• Email User

Plesk will then take care of creating of all the administration - so yes, it will invoke shell commands in the background, but it will also; edit configuration files, create databases, whatever is necessary. Typically, all your packages would be special Plesk-aware versions which are bundled with Plesk - it works much like a Linux distribution in that sense (SUSE and YaST is quite a good comparison, if you are familiar with YaST and it's SuSEconfig perl scripts).

Like most control panel systems, Plesk makes the straight forward, common tasks, very straight forward and easy. If you want to do something a little out of the ordinary (such as making a change to your Apache config. outside of Plesk), you can't just dive in and make the changes, you need to follow Plesk's rules and change it their way. The same could be said for Linux distros (with the possible exception of Slack and Gentoo based), to a lesser or greater extent - e.g. you would be very unwise to make changes to a configuration on a SUSE system without first reading the package's Readme.SUSE

Plesk (and I imagine cPanel) is expensive to buy on it's own - however the big hosting providers get good rates and can often offer it to their customers cheaply or free. E.g. a £30 pm virtual server from 1&1 includes a 100 domain licence for Plesk. There are free alternatives, the first one that springs to mind is Webmin - however it is not oriented to reselling hosting, in the same way as Plesk and cPanel.