update readme with overview of tempalte

README.md

@@ -1,2 +1,93 @@
 # ansible-repository-template
 
+[From ansible best practices](https://docs.ansible.com/ansible/2.8/user_guide/playbooks_best_practices.html)
+
+## Directory Layout
+
+The top level of the directory would contain files and directories like so:
+
+```
+production                # inventory file for production servers
+staging                   # inventory file for staging environment
+
+group_vars/
+   group1.yml             # here we assign variables to particular groups
+   group2.yml
+host_vars/
+   hostname1.yml          # here we assign variables to particular systems
+   hostname2.yml
+
+library/                  # if any custom modules, put them here (optional)
+module_utils/             # if any custom module_utils to support modules, put them here (optional)
+filter_plugins/           # if any custom filter plugins, put them here (optional)
+
+site.yml                  # master playbook
+webservers.yml            # playbook for webserver tier
+dbservers.yml             # playbook for dbserver tier
+
+roles/
+    common/               # this hierarchy represents a "role"
+        tasks/            #
+            main.yml      #  <-- tasks file can include smaller files if warranted
+        handlers/         #
+            main.yml      #  <-- handlers file
+        templates/        #  <-- files for use with the template resource
+            ntp.conf.j2   #  <------- templates end in .j2
+        files/            #
+            bar.txt       #  <-- files for use with the copy resource
+            foo.sh        #  <-- script files for use with the script resource
+        vars/             #
+            main.yml      #  <-- variables associated with this role
+        defaults/         #
+            main.yml      #  <-- default lower priority variables for this role
+        meta/             #
+            main.yml      #  <-- role dependencies
+        library/          # roles can also include custom modules
+        module_utils/     # roles can also include custom module_utils
+        lookup_plugins/   # or other types of plugins, like lookup in this case
+
+    webtier/              # same kind of structure as "common" was above, done for the webtier role
+    monitoring/           # ""
+    fooapp/               # ""
+```
+
+## Alternative Directory Layout
+
+Alternatively you can put each inventory file with its group_vars/host_vars in a separate directory. This is particularly useful if your group_vars/host_vars don’t have that much in common in different environments. The layout could look something like this:
+
+```
+inventories/
+   production/
+      hosts               # inventory file for production servers
+      group_vars/
+         group1.yml       # here we assign variables to particular groups
+         group2.yml
+      host_vars/
+         hostname1.yml    # here we assign variables to particular systems
+         hostname2.yml
+
+   staging/
+      hosts               # inventory file for staging environment
+      group_vars/
+         group1.yml       # here we assign variables to particular groups
+         group2.yml
+      host_vars/
+         stagehost1.yml   # here we assign variables to particular systems
+         stagehost2.yml
+
+library/
+module_utils/
+filter_plugins/
+
+site.yml
+webservers.yml
+dbservers.yml
+
+roles/
+    common/
+    webtier/
+    monitoring/
+    fooapp/
+```
+
+This layout gives you more flexibility for larger environments, as well as a total separation of inventory variables between different environments. The downside is that it is harder to maintain, because there are more files.