Installing a New Site with Drush and Ansible
I found in a comment somewhere deep in the internet that there is a hidden -r option to specify the drupal root within a drush command.

The new play looks like this:


- name: Site Install with Drush
  command: |
    drush si standard --db-url=mysql://{{ mysql_username }}:{{ mysql_password }}@127.0.0.1:3306/{{ mysql_dbname }} --sites-subdir="domain.edu.{{ drupal_uri }}" --db-prefix="d_" -r /vagrant/d7core/ -y
    chdir=/vagrant/d7core/


Note, I also added the -y option, because it will count as an ansible error when it asks you to confirm that you want to DROP ALL ON db.

Because this was hidden functionality and it took me an hour and a half and it was a random comment somewhere that I found that in, I figured I'd make it an official SO question so anyone else looking to automate a workflow could hopefully find this faster.