title needs an update.
I recently switched to using a var for the repo keys instead of a file. The reason for this is that it makes it easier to dump the key on disk by dumping all of the extra vars on our single instance sandbox.  For example here is what we do on the xserver for the content repo where XSERVER_GIT_IDENTITY has the key as a string.

```
- name: install read-only ssh key for the content repo that is required for grading
  copy: >
    content="{{ XSERVER_GIT_IDENTITY }}" dest={{ xserver_git_identity }}
    owner={{ xserver_user }} group={{ xserver_user }} mode=0600
  notify: restart xserver
```