Book Image

Learning Ceph

By : Karan Singh
Book Image

Learning Ceph

By: Karan Singh

Overview of this book

<p>Ceph is an open source, software-defined storage solution, which runs on commodity hardware to provide exabyte-level scalability. It is well known to be a highly reliable storage system that has no single point of failure.</p> <p>This book will give you all the skills you need to plan, deploy, and effectively manage your Ceph cluster, guiding you through an overview of Ceph's technology, architecture, and components. With a step-by-step, tutorial-style explanation of the deployment of each Ceph component, the book will take you through Ceph storage provisioning and integration with OpenStack.</p> <p>You will then discover how to deploy and set up your Ceph cluster, discovering the various components and why we need them. This book takes you from a basic level of knowledge in Ceph to an expert understanding of its most advanced features.</p>
Table of Contents (18 chapters)
Learning Ceph
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Removing the OSD from a Ceph cluster


The process of removing OSDs from a Ceph cluster involves removing all the entries of these OSDs from cluster maps.

Remove the OSDs from the CRUSH map. For this, log in to any of the cluster nodes and perform the following commands:

# ceph osd crush remove osd.9
# ceph osd crush remove osd.10
# ceph osd crush remove osd.11

As soon as OSDs are removed from the CRUSH map, the Ceph cluster becomes healthy. You should also observe the OSD map; since we have not removed the OSDs, it will show as 12 OSD, 9 UP, 9 IN:

Remove the OSD authentication key:

# ceph auth del osd.9
# ceph auth del osd.10
# ceph auth del osd.11

Finally, remove the OSD and check your cluster status. You should see 9 OSD, 9 UP, 9 IN, and the cluster health should be OK:

To keep your cluster clean, perform some housekeeping. As we have removed all the OSDs from the CRUSH map, ceph-node4 does not hold any item. Remove ceph-node4 from the CRUSH map to remove all traces of this node from the Ceph...