• YAML files - All yaml files should use 2 space indents and end with .yaml
• Variables - Use jinja variable syntax over deprecated variable syntax. {{ var }} not $var
• Use spaces around jinja variable names. {{ var }} not {{var}}
• Variables that are environment specific and that need to be overridden should be in ALL CAPS.
• Variables that are internal to the role should be lowercase.
• Prefix all variables defined in a role with the name of the role. Example: EDXAPP_FOO
• Keep roles self contained - Roles should avoid including tasks from other roles when possible
• Plays should do nothing more than include a list of roles except where pre_tasks and post_tasks are required (to manage a load balancer for example)
• Tests - The .gitignore should ignore *test* to allow for local testing without polluting the repository
• Handlers - Any service requiring to restarted should be done via handlers. In other words, no hardcoded reboots of any service to include the host itself.

• Always use when: for conditionals - To check if a variable is defined when: my_var is defined or when: my_var is not defined
• To learn more (see conditional execution)

Break long lines using yaml line continuation

  - debug: >
      msg={{ test }}

  - debug:
      msg: "{{ test }}"

• group_vars/all - Contains variable definitions that apply to all roles.
• "common" role - Contains variables and tasks that apply to all roles.
• Roles variables - Variables specific to a role should be defined in /vars/main.yml. All variables should be prefixed with the role name.
• Variables that are environment specific and that need to be overridden should be in all caps.

• Role names - Terse, lowercase, one word if possible
• Role task names - Terse, descriptive, spaces are OK
• Role handlers - Terse, descriptive, spaces are OK

As a general policy we want to protect the following data:

• Usernames (should be avoided in public repos)
• Public keys (keys are OK to be public)
• Hostnames (should never be hardcoded in play)
• Passwords, API keys (should never be hardcoded in a play)