Small expansion of readme

README.md

@@ -1,8 +1,42 @@
 # hpc-cloud
 
-This repository will contain playbooks to bring up openstack components inside docker containers.
+This repository contains playbooks to bring up openstack components inside docker containers.
+It makes use of ansible roles for the openstack components and the supporting infrastructure.
+The following roles are installed.
+
+### Openstack components.
+
+* keystone
+* glance-controller
+* horizon
+* neutron-controller
+* nova-controller
+* nova-compute
+* cinder-controller
+* cinder-storage
+
+### Auxilary components:
+
+* database (mariadb)
+* rabbitmq (cluster of three nodes)
+* memcached
+
+## Getting started:
+
+### Prerequisites:
+* A cluster of servers to install the components on.
+  * The machines running nova-compute and neutron-controller need a separate interface for neutron to use.
+* ubuntu 16.04 with python installed (usually already present).
+* Access to the webhost12.service.rug.nl docker repository.
+
+### Settings:
+Passwords need be added to `secrets.yml.topol` and it needs to be saved as `secrets.yml`.
+This can be done by running `./generate_secrets.py`.
+Optionally, one can encrypt the secrtets by running `ansible-vault encrypt secrets.yml`.
+
+
+### Secrets:
 
-It makes use of ansible roles.
 The roles can be set in the inventory file (hosts)
 
 To bring up one role, for instance keystone, use: