Update validation role README and defaults

Updated the Bifrost validation role to have default variables
set and updated the documentation to indicate variables that are
likely to differ on customized environments, and included a sample
playbook.

roles/bifrost-validate-host-for-deploy/README.md

@@ -6,22 +6,35 @@ Preforms basic sanity checks of an Ironic node as part of Bifrost host before no
 Requirements
 ------------
 
-TODO
+This role performs basic validation of an Ironic instalation resulting from the execution of the ironic-install role.  As such, that role is required to have been previously executed, however is not required to be executed as part of the same playbook.
 
 Role Variables
 --------------
 
-TODO
+Along the lines of most of the other Bifrost roles, this playbook requires a variable "baremetal_csv_file".  This role does _not_ automatically set or assume the location of this file for the reason that this file must be defined by the user.  This variable is utilized to validate that the file defined is, in fact, a file.
+
+The other variable of note is "deploy_image" which is the image to be deployed to the end host.  If executed in concert with other roles for node deployment, this should be defined as a common variable for all of the roles.
 
 Dependencies
 ------------
 
-TODO
+This role is dependent upon the results of the install-ironic role having been previously applied to the host.
+
+The bifrost-setup-nodes role is dependent upon this role for node validation.
 
 Example Playbook
 ----------------
 
-TODO
+- hosts: localhost
+  connection: local
+  sudo: no
+  vars:
+    baremetal_csv_file: "/path/to/baremetal.csv"
+    deploy_image: "/httpboot/deployment_image.qcow2"
+  roles:
+    - role: bifrost-validate-host-for-deploy
+    - role: bifrost-configdrives
+    - role: bifrost-setup-nodes
 
 License
 -------

roles/bifrost-validate-host-for-deploy/defaults/main.yml

@@ -1,2 +1,5 @@
 ---
 # defaults file for bifrost-validate-host-for-deploy
+http_boot_folder: "/httpboot"
+deploy_image_filename: "deployment_image.qcow2"
+deploy_image: "{{http_boot_folder}}/{{deploy_image_filename}}"