Multisite: Only Drupal Root recognized for subpath

Question

I am having a Drupal 8 multisite installation:

• Hostname: example.com
• 1st Drupal site: in example.com
• 2nd Drupal site: in example.com/sub/path

I have configured this in sites.php:

$sites['example.com.sub.path'] = 'subpath.example.com';
$sites['example.com'] = 'example.com';

The directories example.com and subpath.example.com contain the corresponding settings.php, setting.local.php, etc files.

Additionally, I have added this to the apache configuration (apache 2.4):

DocumentRoot /var/drupal
Alias /sub/path /var/drupal
Alias / /var/drupal
  <Directory /var/drupal/>
    Options Indexes FollowSymLinks
    AllowOverride All
    Include /var/drupal/.htaccess
  </Directory>

The site example.com works as expected. I could install the site example.com/sub/path, but I now can just go to the home page. Every sub-page goes instead to the example.com configuration and gives an appropriate 404 error.

What did I do wrong/overlook?

Any help greatly appreciated!

Answer 1

Adding a rewrite rule into the .htaccess file fixes the problem. Without the rewrite rule for this path, the default rewrite rule goes into effect, pointing to the example.com/index.php instead of example.com/sub/path/index.php.

Disadvantage: I will have to patch .htaccess every time I upgrade Drupal core.

RewriteCond %{REQUEST_URI} ^/sub/path/(.*)$ 
RewriteRule ^(.*)$ /sub/path/index.php [L,QSA]