Multisite Mapping with Drupal

Here I present my recommended settings on Drupal in related to Single Site / Multisite of Drupal Installation by mapping Subdomains and URL's Paths.

To begin this documentation let's take a domain written pure html called www.example.com and a drupal instance as a subdomain called dev.example.com.

The main domain example.com is placed directly at the root of public_html while the drupal instance is placed at public_html/drupal.

Single Drupal Site (Default)

Figure out the structure of our discussed public_html directory along with the domain / subdomain pointing and where the URLs are going as shown below:

/public_html  <-- where example.com, www.example.com, dev.example.com are pointing
    .htaccess         <-- root's .htaccess
    index.html        <-- http://example.com, http://www.example.com
    /drupal               <-- drupal root folder
        .htaccess         <-- drupal's .htaccess
        index.php         <-- http://dev.example.com
        /sites                <-- drupal's file system folder
            /default          <-- drupal's default subfolder 
            setting.php       <-- drupal's default setting (dev.example.com)

URL-Rewriting on root's .htaccess

If the above configuration is the same as yours then I would like to endorse the most reliable code that I got so far for URL-Rewriting on /public_html/.htaccess as follow:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^dev
RewriteCond %{REQUEST_URI} !^/drupal/
RewriteRule ^(.*)$ drupal/$1 [L]

Set the absolute URL on setting.php

To remove the trailing slash of /drupal/ on your URLs, find a line that has the following code:
# $base_url = 'http://www.example.com'; // NO trailing slash!

Remove the leading hash sign and fill in the absolute URL to your Drupal installation as below:
$base_url = 'http://dev.example.com'; // NO trailing slash!

Public file system path

Open your site on your browser. Once you have login to your drupal sites as the admin, check or set the correct path for File system settings under the following admin menu:
Home » Administration » Configuration » Media » File System

Verify or correct the value of Public file system path to:
sites/dev.example.com/files, for your site dev.example.com via access URL:
http://dev.example.com/#overlay=%3Fq%3Dadmin%252Fconfig%252Fmedia%252Ffile-system

Multi Drupal Sites (By Subdomains)

Consider that you want to publish your site dev.example.com under prod.example.com and assign dev.example.com for the futher development.

Here you may simply install a new site, or copy the default folder and duplicate the database follow a guidance on how to copy site that become like so:

/public_html  <-- example.com, www.example.com, dev.example.com, prod.example.com
    .htaccess         <-- root's .htaccess
    index.html        <-- http://example.com, http://www.example.com
    /drupal               <-- drupal root folder
        .htaccess         <-- drupal's .htaccess
        index.php         <-- http://dev.example.com, http://prod.example.com
        /sites                <-- drupal's file system folder
            /default              <-- drupal's default subfolder 
                setting.php       <-- drupal's default setting (prod.example.com)
            /dev.example.com      <-- drupal's dev.example.com subfolder
                setting.php       <-- drupal's dev.example.com setting

By this configuration, instead of /public_html/drupal/sites/default (default folder) your site http://dev.example.com will now follow to the setting.php on folder dev.example.com.

URL-Rewriting on root's .htaccess:

Rewrite the new subdomain of prod along with dev so its URL goes also to drupal but end up automatically to the setting.php on default folder since there is no folder by its name.

RewriteEngine On
RewriteCond %{HTTP_HOST} ^(dev|prod)
RewriteCond %{REQUEST_URI} !^/drupal/
RewriteRule ^(.*)$ drupal/$1 [L]

URL-Rewriting on drupal's .htaccess

Find a line that has the following code:
RewriteRule ^ index.php [L]

Change the code as below:
RewriteRule ^(.*)$ /index.php?q=$1 [L,QSA]

Set the absolute URL on setting.php

Then on each of setting.php remove the leading hash sign $base_url and fill in the absolute URL to your Drupal installation.

Public file system path

Verify or correct the value of Public file system path for every subdomains as below:

• sites/dev.example.com/files, for your site dev.example.com via access URL:
  http://dev.example.com/#overlay=%3Fq%3Dadmin%252Fconfig%252Fmedia%252Ffile-system
• sites/prod.example.com/files, for your site prod.example.com via access URL:
  http://prod.example.com/#overlay=%3Fq%3Dadmin%252Fconfig%252Fmedia%252Ffile-system

Multi Drupal Sites (By Subdomain + URL's Paths)

By sharing the same drupal code base as above (/public_html/drupal) , you may extend the Subdomain Mapping where you can set another drupal sites under URL's Paths like so:

http://dev.example.com/site1,
http://dev.example.com/site2, etc..

Symbolic Links

First you will need to access your server shell. Then create the symbolic links to the drupal root folder named site1 and site2 by following command:

$ cd /path/to/your/public_html/drupal
$ ln -s . site1
$ ln -s . site2

so the directory structure will be as below:

/public_html  <-- example.com, www.example.com, dev.example.com, prod.example.com
    .htaccess         <-- root's .htaccess
    index.html        <-- http://example.com, http://www.example.com
    /drupal               <-- drupal root folder
        .htaccess         <-- drupal's .htaccess
        index.php         <-- http://dev.example.com, http://prod.example.com
        /site1             <-- http://dev.example.com/site1
        /site2             <-- http://dev.example.com/site2
        /sites                <-- drupal's file system folder
            /default          <-- drupal's default subfolder 
                setting.php   <-- drupal's default setting (prod.example.com)
            /dev.example.com        <-- drupal's dev.example.com subfolder
                setting.php         <-- drupal's dev.example.com setting
            /dev.example.com.drupal.site1  <-- drupal's site1 subfolder
                setting.php                <-- drupal's site1 setting
            /dev.example.com.drupal.site2  <-- drupal's site2 subfolder
                setting.php                <-- drupal's site2 setting

Coding on root's .htaccess & setting.php

The code for the root's .htaccess is the same as above, also the step fill in the absolute URL to $base_url in setting.php.

Public file system path

Verify or correct the value of Public file system path for the new sites:

• sites/dev.example.com.drupal.site1/files, for site1 via access URL:
  http://dev.example.com/site1/#overlay=%3Fq%3Dadmin%252Fconfig%252Fmedia%252Ffile-system
• sites/dev.example.com.drupal.site2/files, for site2 via access URL:
  http://dev.example.com/site2/#overlay=%3Fq%3Dadmin%252Fconfig%252Fmedia%252Ffile-system

Multi Drupal Sites (By Drupal 8)

By Drupal 8 the symbolic links are no more required, there even a flexibility to name the folders under /public_html/drupal/sites as long you put them on the file sites.php like:

$sites = array(
   'dev.example.com' => 'dev',
   'dev.example.com.site1' => 'dev.site1',
   'dev.example.com.site2' => 'dev.site2',
);

so the directory structure will be as below:

/public_html  <-- example.com, www.example.com, dev.example.com, prod.example.com
    .htaccess         <-- root's .htaccess
    index.html        <-- http://example.com, http://www.example.com
    /drupal               <-- drupal root folder
        .htaccess         <-- drupal's .htaccess
        index.php         <-- http://dev.example.com, http://prod.example.com
        /sites                <-- drupal's file system folder
            sites.php         <-- drupal's multisite setting
            /default          <-- drupal's default subfolder 
                setting.php   <-- drupal's default setting (prod.example.com)
            /dev                  <-- drupal's dev.example.com subfolder
                setting.php       <-- drupal's dev.example.com setting
            /dev.site1            <-- drupal's dev.example.com.site1 subfolder
                setting.php       <-- drupal's dev.example.com.site1 setting
            /dev.site2            <-- drupal's dev.example.com.site2 subfolder
                setting.php       <-- drupal's dev.example.com.site2 setting

Optional Settings

Clean URLs

If you like to use URLs like dev.example.com/user instead of dev.example.com/?q=user, you will need to enable Clean URLs for your site by accessing the following menu:
Home » Administration » Configuration » Search and metadata » Clean URLs

Incase a trouble with Clean URLs, you may add the following at the end line of setting.php:
$GLOBALS['conf']['clean_url'] = 0;

SEO URLs

You may also set a SEO Friendly URLs using URL Aliases by accessing the following menu:
Home » Administration » Configuration » Search and metadata » URL aliases

Just remember to avoid the same URL path like the ones listed below when you set your Multi-site by Subdomain + URL's Paths otherwise it will mix up your Multisite setting.

http://dev.example.com/site1
http://dev.example.com/site2

Copy Site

You may want to duplicate your site by a Multisite setup for testing or development purposes. Following are documentation you can follow:

• Create a Test Site
• Making a duplicate of a Drupal website
• Easy method to create duplicate of production site for testing

You may also use my method as below. The command is made with an assumption that you have already a backup folder and an existing production site. Please use it with caution.

#COPY FOLDER (sites/dev » sites/prod)
$ cd /path-to-your/public_html/drupal/sites;
$ sudo rm -rf backup/dev;
$ sudo rsync -aczvAXHS --progress dev backup;
$ sudo mv prod backup/;
$ sudo mv backup/dev prod;
$ find prod -type d -exec sudo chmod 2775 {} \;
$ find prod -type f -exec sudo chmod 0664 {} \;
$ cd prod;
$ find settings.php -type f -exec sudo sed -i 's/db-dev/db-prod/g' {} \;
$ find settings.php -type f -exec sudo sed -i 's/sites\/dev\/files/sites\/prod\/files/g' {} \;

#COPY DATABASE (db-dev » db-prod)
$ sudo rm -rf backup/prod.sql;
$ mysqldump -uUSERNAME -pPASSWORD db-prod > backup/prod.sql;
$ sudo rm -rf backup/dev.sql;
$ mysqldump -uUSERNAME -pPASSWORD db-dev > backup/dev.sql;
$ find backup/dev.sql -type f -exec sed -i 's/db-dev/db-prod/g' {} \;
$ mysql -uADMINNAME -pPASSWORD;
$ mysql> SHOW DATABASES;
$ mysql> DROP DATABASE `db-prod`;
$ mysql> CREATE DATABASE `db-prod` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
$ mysql> GRANT ALL PRIVILEGES ON `db-prod`.* TO "USERNAME"@"localhost";
$ mysql> FLUSH PRIVILEGES;
$ mysql> exit;
$ mysql -uUSERNAME -pPASSWORD db-prod < backup/dev.sql;
$ rm -rf backup/dev.sql;

Cache Clearing

Last but not least, to make sure everything is set properly, it is recommended to do a Cache Clearing whenever you have put a new setting on your sites by accessing the following menu:
Home » Administration » Configuration » Development » Clear all Caches

Using Drush you can even do it for all of your Multisite with one time cache command:

$ cd /path/to/your/public_html/drupal
$ drush @sites cache-rebuild

Recommendation

You may setup Drupal Multisite grouped by the followings, hopefully you can find out on how it looks like.

• Sharing Drupal Core Base with Different Theme & Database
• Sharing Drupal Database with Different Layout Themes
• Sharing Drupal Theme with Different Database