Chapter 1. Introduction
The Red Hat OpenStack Platform director is a toolset for installing and managing a complete OpenStack environment. It is based primarily on the OpenStack project TripleO, which is an abbreviation for "OpenStack-On-OpenStack". This project takes advantage of OpenStack components to install a fully operational OpenStack environment; this includes new OpenStack components that provision and control bare metal systems to use as OpenStack nodes. This provides a simple method for installing a complete Red Hat OpenStack Platform environment that is both lean and robust.
The Red Hat OpenStack Platform director uses two main concepts: an Undercloud and an Overcloud. The Undercloud installs and configures the Overcloud. The next few sections outline the concept of each.
Figure 1.1. Basic Layout of Undercloud and Overcloud
1.1. Undercloud
The Undercloud is the main director node. It is a single-system OpenStack installation that includes components for provisioning and managing the OpenStack nodes that form your OpenStack environment (the Overcloud). The components that form the Undercloud provide the following functions:
- Environment planning - The Undercloud provides planning functions for users to assign Red Hat OpenStack Platform roles, including Compute, Controller, and various storage roles.
- Bare metal system control - The Undercloud uses the Intelligent Platform Management Interface (IPMI) of each node for power management control and a PXE-based service to discover hardware attributes and install OpenStack to each node. This provides a method to provision bare metal systems as OpenStack nodes.
- Orchestration - The Undercloud provides and reads a set of YAML templates to create an OpenStack environment.
The Red Hat OpenStack Platform director performs these Undercloud functions through a terminal-based command line interface.
The Undercloud consists of the following components:
- OpenStack Bare Metal (ironic) and OpenStack Compute (nova) - Manages bare metal nodes.
- OpenStack Networking (neutron) and Open vSwitch - Controls networking for bare metal nodes.
- OpenStack Image Service (glance) - Stores images that are written to bare metal machines.
- OpenStack Orchestration (heat) and Puppet - Provides orchestration of nodes and configuration of nodes after the director writes the Overcloud image to disk.
- OpenStack Telemetry (ceilometer) - Performs monitoring and data collection.
- OpenStack Identity (keystone) - Provides authentication and authorization for the director's components.
- MariaDB - The database back end for the director.
- RabbitMQ - Messaging queue for the director's components.
