Chapter 1. Introduction

Red Hat OpenStack Platform director creates a cloud environment called the overcloud. The director provides the ability to configure extra features for an overcloud, including integration with Red Hat Ceph Storage (both Ceph Storage clusters created with the director or existing Ceph Storage clusters).

1.1. Introduction to Ceph Storage

Red Hat Ceph Storage is a distributed data object store designed to provide excellent performance, reliability, and scalability. Distributed object stores are the future of storage, because they accommodate unstructured data, and because clients can use modern object interfaces and legacy interfaces simultaneously. At the heart of every Ceph deployment is the Ceph Storage Cluster, which consists of two types of daemons:

Ceph OSD (Object Storage Daemon)
Ceph OSDs store data on behalf of Ceph clients. Additionally, Ceph OSDs utilize the CPU and memory of Ceph nodes to perform data replication, rebalancing, recovery, monitoring and reporting functions.
Ceph Monitor
A Ceph monitor maintains a master copy of the Ceph storage cluster map with the current state of the storage cluster.

For more information about Red Hat Ceph Storage, see the Red Hat Ceph Storage Architecture Guide.

Important

This guide contains integration information for Ceph Block storage and the Ceph Object Gateway (RGW). It does not include information about Ceph File (CephFS) storage.

1.2. Defining the Scenario

This guide provides instructions on integrating an existing Ceph Storage cluster with an overcloud. This means the director configures the overcloud to use the Ceph Storage cluster for storage needs. You manage and scale the cluster itself outside of the Overcloud configuration.