Book Image

Ceph Cookbook

Book Image

Ceph Cookbook

Overview of this book

Ceph is a unified, distributed storage system designed for excellent performance, reliability, and scalability. This cutting-edge technology has been transforming the storage industry, and is evolving rapidly as a leader in software-defined storage space, extending full support to cloud platforms such as Openstack and Cloudstack, including virtualization platforms. It is the most popular storage backend for Openstack, public, and private clouds, so is the first choice for a storage solution. Ceph is backed by RedHat and is developed by a thriving open source community of individual developers as well as several companies across the globe. This book takes you from a basic knowledge of Ceph to an expert understanding of the most advanced features, walking you through building up a production-grade Ceph storage cluster and helping you develop all the skills you need to plan, deploy, and effectively manage your Ceph cluster. Beginning with the basics, you’ll create a Ceph cluster, followed by block, object, and file storage provisioning. Next, you’ll get a step-by-step tutorial on integrating it with OpenStack and building a Dropbox-like object storage solution. We’ll also take a look at federated architecture and CephFS, and you’ll dive into Calamari and VSM for monitoring the Ceph environment. You’ll develop expert knowledge on troubleshooting and benchmarking your Ceph storage cluster. Finally, you’ll get to grips with the best practices to operate Ceph in a production environment.
Table of Contents (18 chapters)
Ceph Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

CRUSH map internals


To know what is inside a crush map, and for easy editing we need to extract and decompile it to convert it into a human-readable form. The following diagram illustrates this process:

The change to the Ceph cluster by the CRUSH map is dynamic, that is, once the new crush map is injected into the Ceph cluster, all the changes will come into effect immediately, on the fly.

How to do it…

We will now take a look at the CRUSH map of our Ceph cluster:

  1. Extract the CRUSH map from any of the monitor nodes:

    # ceph osd getcrushmap -o crushmap_compiled_file
    
  2. Once you have the CRUSH map, decompile it to convert it into a human-readable/editable form:

    # crushtool -d crushmap_compiled_file -o crushmap_decompiled_file
    

    At this point, the output file, crushmap_decompiled_file, can be viewed/edited in your favorite editor. In the next recipe, we will learn how to perform changes to the CRUSH map.

  3. Once the changes are done, you should compile these changes:

    # crushtool -c crushmap_decompiled_file...