defined input parameters in README

Author: hollysilk

README.md

@@ -4,6 +4,23 @@
 
 This Ansible role is used to install the necessary packages to have a fully functional OpenHPC cluster.
 
+Role Variables
+--------------
+
+`openhpc_slurm_service_enabled`: checks whether `openhpc_slurm_service` is enabled
+`openhpc_slurm_service`: name of the slurm service e.g. `slurmd`
+`openhpc_slurm_control_host`: ansible host name of the controller e.g `"{{ groups['cluster_login'] | first }}"`
+`openhpc_slurm_partitions`: list of slurm partitions
+`openhpc_cluster_name`: name of the cluster
+`openhpc_packages`: additional OpenHPC packages to install
+`openhpc_enable`: 
+* `control`: whether to enable control host
+* `batch`: whether to enable compute nodes 
+* `runtime`: whether to enable OpenHPC runtime
+
+Example Playbook
+----------------
+ 
 To deploy, create a playbook which looks like this:
 
     ---
@@ -17,8 +34,17 @@ To deploy, create a playbook which looks like this:
             control: "{{ inventory_hostname in groups['cluster_control'] }}"
             batch: "{{ inventory_hostname in groups['cluster_batch'] }}"
             runtime: true
+          openhpc_slurm_service_enabled: true
+          openhpc_slurm_service: slurmd
+          openhpc_slurm_control_host:
+          openhpc_slurm_partitions: []
+          openhpc_cluster_name:
+          openhpc_packages: []
     ...
 
+Example Inventory
+-----------------
+
 And an Ansible inventory as this:
 
     [openhpc_login]