Moving INSTALL.md to docs directory and adding PREINSTALL.md file

Signed-off-by: Lucas A. Wilson <luke.wilson@dell.com>

docs/PREINSTALL.md

@@ -0,0 +1,18 @@
+# Pre-Installation Preparation
+
+## Assumptions
+Omnia assumes that prior to installation:
+* Systems have a base operating system (currently CentOS 7 or 8)
+* Network(s) has been cabled and nodes can reach the internet
+* SSH Keys for `root` have been installed on all nodes to allow for password-less SSH
+* Ansible is installed on the master node
+```
+yum install ansible
+```
+
+## Example system designs
+Omnia can configure systems which use Ethernet- or Infiniband-based fabric to connect the compute servers.
+
+![Example system configuration with Ethernet fabric](images/example-system-ethernet.png)
+
+![Example system configuration with Infiniband fabric](images/example-system-infiniband.png)