If you already have a Drupal codebase on your host machine (e.g. in ~/Sites/my-drupal-site), and don't want or need to build your Drupal site with a Drush make file, make the following changes to config.yml before building Drupal VM:

Sync your Drupal codebase to the VM

Update the vagrant_synced_folders configuration to sync your local Drupal codebase to a folder within the machine:

vagrant_synced_folders:
  - local_path: ~/Sites/my-drupal-site
    destination: /var/www/my-drupal-site
    type: nfs

If you have Drupal VM installed within your codebase, you can also set the local_path to a location relative to the Vagrantfile. This is the default setup in default.config.yml.

Disable the Composer project build and site install

Set all the drupal_build_* variables and install_site to false:

drupal_build_makefile: false
drupal_build_composer: false
drupal_build_composer_project: false
...
drupal_install_site: false

If you aren't copying back a database, and want to have Drupal VM run drush si for your Drupal site, you can leave drupal_install_site set to true and it will run a site install on your Drupal codebase using the drupal_* config variables.

Update drupal_core_path

Set drupal_core_path to the same value as the destination of the synced folder you configured earlier:

drupal_core_path: "/var/www/my-drupal-site"

This variable will be used for the document root of the webserver.

Set the domain

By default the domain of your site will be drupalvm.dev but you can change it by setting drupal_domain to the domain of your choice:

drupal_domain: "local.my-drupal-site.com"

If you prefer using your domain as the root of all extra packages installed, ie. adminer, xhprof and pimpmylog, set it as the value of vagrant_hostname instead.

vagrant_hostname: "my-drupal-site.com"
drupal_domain: "{{ vagrant_hostname }}"

Update MySQL info

If you have your Drupal site configured to use a special database and/or user/password for local development (e.g. through a settings.local.php file), you can update the values for mysql_databases and mysql_users as well.

Build the VM, import your database

Run vagrant up to build the VM with your codebase synced into the proper location. Once the VM is created, you can connect to the MySQL database and import your site's database to the Drupal VM, or use a command like drush sql-sync to copy a database from another server.