Based on mod_vhost_alias to add fallback folder
-
Install apache dev tools
apt install -y apache2-dev -
Compile
apxs -i -a -c mod_vhost_alias_fallback.c
# Subdomains mydomain.tld
# Load module
LoadModule vhost_alias_fallback_module /usr/lib/apache2/modules/mod_vhost_alias_fallback.so
<VirtualHost *:80>
ServerAlias *.mydomain.tld
UseCanonicalName Off
# Use VirtualDocumentRootWithFallback directive
VirtualDocumentRootWithFallback /usr/local/apache2/websites/subdomains/%1 usr/local/apache2/websites/subdomains/default
</VirtualHost>