The subsites module allows multiple websites to run from a single installation of SilverStripe, and share users, content, and assets between them. A useful way to think of its use is where you have a business with a global headquarters and four branches in various countries. The subsites module allows the five offices to use a single SilverStripe installation, and have information from the headquarters flow down into the branches. The branches can have separate users/admins, and information that is individual. The website templates can also be different.
* Create necessary tables by visiting `http://<yoursite>/dev/build` (you should see a `Subsite` table created, among other things). You don't need to run this command for every subsite.
* Login to the CMS as an administrator. You should now see a "Subsites" entry on the main menu, access that section now.
* Hit the "Add Subsite" button to create a new subsite.
* Once you've created a subsite, you'll see a "Create Subsite Domain" button, hit that button to enter a domain or subdomain for your subsite. This will determine the URL of your website. For example, if your site is running on `http://localhost/mysite`, and you set the subdomain to "subsite", then your subsite will be accessible on `http://subsite.localhost/mysite`
* Go to the "Pages" section of the CMS. In the top-left above the menu, you'll see a dropdown listing the two subsites - "Main site" is the original site that you had before you installed the subsites module. Select your new subsite, and the site content tree will be changed. It should be empty at this stage.
* Add a page - change its title to "Home", and its URL Segment will be changed to "home". Save the page.
* Update your DNS and, if necessary, your webserver configuration, so that your subdomain will point to the SilverStripe installation on your webserver. Visit this new subdomain. You should see the new subsite homepage.
You can list available domains for your subsites (Example: subdomain.''domain''.tld). The subsites are generally identified only by their subdomain part (Example: ''subdomain''.domain.tld).
This example would let you create subsites such as ''wellington.mycompany.com'' or ''london.mycompany.org''
If you would like to be able to choose any domain for your subsite, rather than subdomains off a common base, then list top-level domains in your `set_allowed_domains()` list.
In this example, your subsite name (e.g. ''silverstripe''), will be appended to a much shorter base domain (e.g. ''co.nz'', or ''org''). This would let you create subsites with domains such as ''silverstripe.org'' or ''example.co.nz''
You can mix the two together, if you want to have some subsites hosted off subdomains of your mail site, and some subsites hosted off their own domains. In this example, you could set up subsites at ''wellington.example.com'', ''othersite.co.nz'', or ''thirdsite.org''.
*mysite/_config.php*
:::php
Subsite::set_allowed_domains(array(
'example.com',
'com',
'org',
'co.nz',
'org.nz',
));
Note that every site also has a ''www.''-prefixed version of the domain available. For example, if your subsite is accessible from ''wellington.example.org'' then it will also be accessible from '''www.wellington.example.org''.
Download a second theme from http://www.silverstripe.com/themes/ and put it in your themes folder. Open admin/subsites?flush=1 and select one of your subsites from the menu on the bottom-left. You should see a Theme dropdown in the subsite details, and it should list both your original theme and the new theme. Select the new theme in the dropdown. Now, this subsite will use a different theme from the main site.
### Limit available themes for a subsite
Not all themes might be suitable or adapted for all subsites. You can optionally limit usage of themes: