This is a hybrid solution for the Drupal's multisite installation.

A "multi-site" allows you to run many sites from a single codebase. The idea is that you can update the codebase once and automatically apply those changes to all your site. In theory, it's a great idea. In practice, it often causes more problems than it solves.

The most obvious problem of running a lot of sites on one codebase is that any one of them could face a traffic spike, and negatively impact all the others. If you're looking to serve a large volume of sites, the risk becomes non-trivial that one site's "best day ever" is the other 99's worst.

One syntax error, and all the sites go down.

Updating the codebase would require running update scripts for all the websites nevertheless. There's also the reality that some upgrades may not go smoothly.

Adding or modifying codebase for a specific website may effect other websites within the multi-site environment. Code-freeze and/or content-freeze might be needed for rest of the websites.

Configuring content access rules are more complicated and restrictive. Also, changing the behavior at a later stage is often more restrictive and troublesome. Similar hurdles also present for the users managing the content for the websites. Especially when moderation logic is part of the content administration.

Multi-site environments are not supported by all hosting platforms. Pantheon.io which hosts most of our Drupal projects, is one of them. Pantheon argues why multi-site configuration is not good.

Why Drupal Multisite Is Not Enterprise Grade https://pantheon.io/blog/why-drupal-multisite-not-enterprise-grade

Drupal Multisite: Much Ado About Drupal Multisite https://pantheon.io/blog/drupal-multisite-much-ado-about-drupal-multisite

Acquia on the other hand, is the company founded by the creator of Drupal CMS, Dries Buytaert. And Acquia, offers 3-tier environment similar to Pantheon development, staging and production. On the contrast to Pantheon, Acquia supports multi-site configuration and promotes it as a selling point. See attached PDF document offered by Acquia for details.

In our experience, multi-site configuration speeds up development in early stages. However, once the sites need unique features which would not be shared with others, complications starts. Maintaining, the sites, the content and the users becomes more challenging as the web sites grow.

This project uses a single Drupal core and single shared sites/all directory to manage multiple websites by utilizing Grunt task runner.

As for the Drupal core, Pantheon's drop-7 could be used as a Git sub-module.

# Clone project from Github.
git clone git@github.com:gormus/multisite.git my_multisite_project
cd my_multisite_project
# Install grunt-cli globally.
npm install -g grunt-cli
# Install project locallyin current directory.
npm install
# Add Drupal as a git submodule. See config.path.drupal_core in config.json for the desired Drupal core directory.
git submodule add git@github.com:pantheon-systems/drops-7.git drupal_core
git submodule update --init
git commit ./drupal_core/ -m "Added Pantheon's drop-7 repo as a submodule."

grunt new:example.com

grunt update:example.com

grunt update:all

grunt stage:example.com

grunt deploy:example.com

grunt clone:example.com --source=[development|staging|production] --target=[development|staging|production]

grunt backup:example.com --env=[development|staging|production]

grunt empty:example.com --env=[development|staging|production]

The Gruntfile.js can generate a site-aliases file to be used with Drush: aliases.drushrc.php.

grunt create-site-aliases
grunt update-site-aliases

To access the dynamically generated aliases include --alias-path=. argument in the drush command.

drush --alias-path=. @dev.example.com status
drush --alias-path=. @dev.example.com cache-clear all

Add these features:

grunt drupal:update

git pull origin/master
git submodule update

/**
 * File system.
 */
$conf['file_default_scheme'] = 'public';
$conf['file_temporary_path'] = '/Applications/MAMP/tmp/php';
$conf['file_public_path']    = 'sites/example.dev/public_files';
$conf['file_private_path']   = 'sites/example.dev/private_files';

/**
 * Regional settings.
 */
$conf['site_default_country'] = 'US';
$conf['date_default_timezone'] = 'America/Los_Angeles';

/**
 * Account settings.
 */
$conf['user_register'] = '0';
$conf['user_pictures'] = 0;
$conf['user_signatures'] = 0;