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. One of these extra features includes integration with Red Hat Ceph Storage. This includes both Ceph Storage clusters created with the director or existing Ceph Storage clusters.

The Red Hat Ceph cluster described in this guide features containerized Ceph Storage. For more information about containerized services in OpenStack, see "Configuring a Basic Overcloud with the CLI Tools" in the Director Installation and Usage Guide.

1.1. Defining 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 only integrates Ceph Block storage and the Ceph Object Gateway (RGW). It does not include Ceph File (CephFS) storage.

1.2. Defining the Scenario

This guide provides instructions for deploying a containerized Red Hat Ceph cluster with your overcloud. To do this, the director uses Ansible playbooks provided through the ceph-ansible package. The director also manages the configuration and scaling operations of the cluster.

1.3. Setting Requirements

This guide acts as supplementary information for the Director Installation and Usage guide. This means the Requirements section also applies to this guide. Implement these requirements as necessary.

If using the Red Hat OpenStack Platform director to create Ceph Storage nodes, note the following requirements for these nodes:

Processor
64-bit x86 processor with support for the Intel 64 or AMD64 CPU extensions.
Memory
Memory requirements depend on the amount of storage space. Ideally, use at minimum 1 GB of memory per 1 TB of hard disk space.
Disk Space
Storage requirements depends on the amount of memory. Ideally, use at minimum 1 GB of memory per 1 TB of hard disk space.
Disk Layout

The recommended Red Hat Ceph Storage node configuration requires at least three or more disks in a layout similar to the following:

  • /dev/sda - The root disk. The director copies the main Overcloud image to the disk.
  • /dev/sdb - The journal disk. This disk divides into partitions for Ceph OSD journals. For example, /dev/sdb1, /dev/sdb2, /dev/sdb3, and onward. The journal disk is usually a solid state drive (SSD) to aid with system performance.

  • /dev/sdc and onward - The OSD disks. Use as many disks as necessary for your storage requirements.

    Note

    Red Hat OpenStack Platform director uses ceph-ansible, which does not support installing the OSD on the root disk of Ceph Storage nodes. This means you need at least two or more disks for a supported Ceph Storage node.

Network Interface Cards
A minimum of one 1 Gbps Network Interface Cards, although it is recommended to use at least two NICs in a production environment. Use additional network interface cards for bonded interfaces or to delegate tagged VLAN traffic. It is recommended to use a 10 Gbps interface for storage node, especially if creating an OpenStack Platform environment that serves a high volume of traffic.
Power Management
Each Controller node requires a supported power management interface, such as an Intelligent Platform Management Interface (IPMI) functionality, on the server’s motherboard.

This guide also requires the following:

Important

The Ceph Monitor service is installed on the Overcloud’s Controller nodes. This means you must provide adequate resources to alleviate performance issues. Ensure the Controller nodes in your environment use at least 16 GB of RAM for memory and solid-state drive (SSD) storage for the Ceph monitor data.

1.4. Additional Resources

The /usr/share/openstack-tripleo-heat-templates/environments/ceph-ansible/ceph-ansible.yaml environment file instructs the director to use playbooks derived from the ceph-ansible project. These playbooks are installed in /usr/share/ceph-ansible/ of the undercloud. In particular, the following file lists all the default settings applied by the playbooks:

  • /usr/share/ceph-ansible/group_vars/all.yml.sample
Warning

While ceph-ansible uses playbooks to deploy containerized Ceph Storage, do not edit these files to customize your deployment. Doing this will result in a failed deployment. Rather, use Heat environment files to override the defaults set by these playbooks.

You can also consult the documentation of this project (http://docs.ceph.com/ceph-ansible/master/) to learn more about the playbook collection.

Alternatively, you can also consult the Heat templates in /usr/share/openstack-tripleo-heat-templates/docker/services/ceph-ansible/ for information about the default settings applied by director for containerized Ceph Storage.

Note

Reading these templates requires a deeper understanding of how environment files and Heat templates work in director. See Understanding Heat Templates and Environment Files for reference.

Lastly, for more information about containerized services in OpenStack, see "Configuring a Basic Overcloud with the CLI Tools" in the Director Installation and Usage Guide.