Book Image

Learning Ceph - Second Edition

By : Karan Singh, Vaibhav Bhembre, Anthony D'Atri
Book Image

Learning Ceph - Second Edition

By: Karan Singh, Vaibhav Bhembre, Anthony D'Atri

Overview of this book

Learning Ceph, Second Edition will give you all the skills you need to plan, deploy, and effectively manage your Ceph cluster. You will begin with the first module, where you will be introduced to Ceph use cases, its architecture, and core projects. In the next module, you will learn to set up a test cluster, using Ceph clusters and hardware selection. After you have learned to use Ceph clusters, the next module will teach you how to monitor cluster health, improve performance, and troubleshoot any issues that arise. In the last module, you will learn to integrate Ceph with other tools such as OpenStack, Glance, Manila, Swift, and Cinder. By the end of the book you will have learned to use Ceph effectively for your data storage requirements.
Table of Contents (18 chapters)
Title Page
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Monitoring Ceph MONs


A proper Ceph cluster comprises three or more Monitor daemons, ideally situated on distinct physical servers. As discussed in Chapter 4, Planning your Deployment, multiple MONs are recommended to ensure fault tolerance and maintainability. If a cluster's MONs cannot form a quorum, which happens if not enough of the provisioned MONs are up, then new clients won't be able to connect to the system. Worse yet, existing clients will no longer be able to perform operations once their sessions expire. It is paramount for cluster health to have a majority of MONs up and able to fulfill their quorum duties.

MON status

We can retrieve basic information about all MONs in the cluster by running the ceph utility's mon stat subcommand. If our clusters contains MONs that are down or unavailable and thus have been temporarily kicked out of quorum, this command will alert us to the situation so that we can address it.

root@ceph-client0:~# ceph mon stat
e1: 1 mons at {ceph-mon0=192.168.42...