Drupal Multisite

The following guide outlines the steps needed to configure a Drupal 8 multisite setup. This guide is a work in progress and includes only sample configurations. Other options—such as HTTPS, different web servers and databases, or advanced virtual host configurations—are available.

It is worth noting that using the Aegir hosting system is the preferred method. Aegir automates the complex setup process using secure best practices, including automatic virtual host configuration for Apache and Nginx, HTTPS support, Composer command execution, and more. See the Platform Setup Documentation—Aegir-speak for a multisite codebase.

Process Overview:

1. Install a Drupal 8 instance that will act as the root site of our multisite installation. In this example, the root site will be named d8multisite, accessible at d8multisite.com and installed at /var/www/d8multisite.

2. Create a multisite named site1, accessible at site1.d8multisite.com.

3. Configure site1 to have its own modules independent of the root site.

Step 1: Create the Master Site

Start by installing a copy of Drupal 8 on your server. Refer to the Drupal 8 Installation Documentation if you're unfamiliar with the process.

1.1: Create a database for the root site, e.g., d8multisite.

1.2: Download and extract Drupal 8 into your web root.

1.3: Create a virtual host definition for the root site. See virtual host configuration. Apache example:

  ServerAdmin me@domain.com
  DocumentRoot /var/www/d8multisite
  ServerName d8multisite.com
  ServerAlias www.d8multisite.com

  
    Options FollowSymLinks
    AllowOverride None
  

  
    Options Indexes FollowSymLinks MultiViews
    AllowOverride All
    Require all granted
  

  ErrorLog ${APACHE_LOG_DIR}/d8multisite_error.log
  LogLevel warn
  CustomLog ${APACHE_LOG_DIR}/d8multisite_access.log combined

1.4: Complete the Drupal installation at d8multisite.com.

Step 2: Configure First Multisite Instance

2.1: Create a folder for site1: /d8multisite/sites/site1.d8multisite.com

2.2: Create a new database for site1, e.g., d8multisite_site1

2.3: Copy example.sites.php to sites.php

cp sites/example.sites.php sites/sites.php

2.4: Edit sites.php and append:

$sites['site1.d8multisite.com'] = 'site1.d8multisite.com';

2.5: Create a virtual host for site1:

  ServerAdmin me@domain.com
  DocumentRoot /var/www/d8multisite
  ServerName site1.d8multisite.com

  
    Options FollowSymLinks
    AllowOverride None
  

  
    Options Indexes FollowSymLinks MultiViews
    AllowOverride All
    Require all granted
  

  ErrorLog ${APACHE_LOG_DIR}/site1-d8multisite_error.log
  LogLevel warn
  CustomLog ${APACHE_LOG_DIR}/site1-d8multisite_access.log combined

2.6: Copy the default settings file into the new site folder:

cp sites/default/default.settings.php sites/site1.d8multisite.com/settings.php

2.7: Visit site1.d8multisite.com to complete the Drupal installation.

Step 3: Enable Site-Specific Modules

To allow site1 to have its own modules:

1. Create a modules folder in site1: /d8multisite/sites/site1.d8multisite.com/modules
2. Give Apache write permissions: chown www-data /d8multisite/sites/site1.d8multisite.com/modules
3. Verify:
   • Install Pathauto in the root site via Drush: drush dl pathauto
   • Switch to the site1 directory and install Display Suite: drush dl ds
   • Confirm that:
     • Pathauto is available on both sites
     • Display Suite is only available on site1

Note: This applies similarly to themes, libraries, and files. Further testing and documentation is needed.

Using Drush with Multisites

You can use the -l option:

drush -l example.com command

Or use a site alias:

drush @alias command

To view site aliases:

drush site:alias

Example output:

@sub1.dev:
root: /var/www/mydomain.com/web
uri: "https://sub1.mydomain.com"
@default.dev:
root: /var/www/mydomain.com/web
uri: "https://sub2.mydomain.com"
@third.dev:
root: /var/www/mydomain.com/web
uri: "https://thirddomain.com"

To run a Drush command for a specific site:

drush @sub1 updb

Note: Avoid using ".dev" in the alias name itself.