1 files changed, 34 insertions, 4 deletions
diff --git a/docs/style_guide.adoc b/docs/style_guide.adoc
index 3b888db12..09d4839c7 100644
--- a/docs/style_guide.adoc
+++ b/docs/style_guide.adoc
@@ -1,6 +1,6 @@
 // vim: ft=asciidoc
 
-= Openshift-Ansible Style Guide
+= openshift-ansible Style Guide
 
 The purpose of this guide is to describe the preferred coding conventions used in this repository (both in ansible and python).
 
@@ -43,18 +43,48 @@ This is a hard limit and is enforced by the build bot. This check MUST NOT be di
 
 == Ansible
 
-=== Ansible Global Variables
-Ansible global variables are defined as any variables outside of ansible roles. Examples include playbook variables, variables passed in on the cli, etc.
 
+=== Ansible Yaml file extension
+'''
+[cols="2v,v"]
+|===
+| **Rule**
+| All Ansible Yaml files MUST have a .yml extension (and NOT .YML, .yaml etc).
+|===
+
+Ansible tooling (like `ansible-galaxy init`) create files with a .yml extension. Also, the Ansible documentation website references files with a .yml extension several times. Because of this, it is normal in the Ansible community to use a .yml extension for all Ansible Yaml files.
+
+Example: `tasks.yml`
+
+
+=== Ansible CLI Variables
+'''
+[cols="2v,v"]
+|===
+| **Rule**
+| Variables meant to be passed in from the ansible CLI MUST have a prefix of cli_
+|===
+
+Ansible allows variables to be passed in on the command line using the `-e` option. These variables MUST have a prefix of cli_ so that it's clear where they came from, and that they could be exploited.
+
+
+.Example:
+[source]
+----
+ansible-playbook -e cli_foo=bar someplays.yml
+----
+
+=== Ansible Global Variables
 '''
 [cols="2v,v"]
 |===
 | **Rule**
 | Global variables MUST have a prefix of g_
 |===
+Ansible global variables are defined as any variables outside of ansible roles. Examples include playbook variables, variables passed in on the cli, etc.
 
 
-Example:
+.Example:
 [source]
 ----
 g_environment: someval