title: Prevent simultaneous deploys with Ansible
body: <p>Anyone on my team can SSH into our special deploy server, and from there run an Ansible playbook to push new code to machines.</p>
  
  <p>We're worried about what will happen if two people try to do deploys simultaneously. We'd like to make it so that the playbook will fail if anyone else is currently running it.</p>
  
  <p>Any suggestions for how to do this? The standard solution is to use a pid file, but Ansible does not have built-in support for these.</p>