Book Image

Mastering Proxmox - Third Edition

By : Wasim Ahmed
4 (1)
Book Image

Mastering Proxmox - Third Edition

4 (1)
By: Wasim Ahmed

Overview of this book

Proxmox is an open source server virtualization solution that has enterprise-class features for managing virtual machines, for storage, and to virtualize both Linux and Windows application workloads. You'll begin with a refresher on the advanced installation features and the Proxmox GUI to familiarize yourself with the Proxmox VE hypervisor. Then, you'll move on to explore Proxmox under the hood, focusing on storage systems, such as Ceph, used with Proxmox. Moving on, you'll learn to manage KVM virtual machines, deploy Linux containers fast, and see how networking is handled in Proxmox. You'll also learn how to protect a cluster or a VM with a firewall and explore the new high availability features introduced in Proxmox VE 5.0. Next, you'll dive deeper into the backup/restore strategy and see how to properly update and upgrade a Proxmox node. Later, you'll learn how to monitor a Proxmox cluster and all of its components using Zabbix. Finally, you'll discover how to recover Promox from disaster strikes through some real-world examples. By the end of the book, you'll be an expert at making Proxmox work in production environments with minimal downtime.
Table of Contents (23 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Recovering from a quorum failure


There are various reason why a Proxmox cluster can lose a quorum. For the cluster to operate correctly, a quorum must exist within the nodes. A quorum is established when the majority of the nodes are online. If 51% of the nodes go offline for whatever reason, a quorum will be lost, resulting in a cluster error. A Proxmox quorum relies on multicast. So if multicast gets disabled in the switch, the cluster can also lose a quorum. A manual misconfiguration in the cluster file can also cause loss of a quorum. When a quorum is lost, the following error messages will appear in log files under /var/log/corosync:

......................
corosync[9999]:  [QUORUM] Quorum provider: corosync_votequorum failed to initialize.
corosync[9999]:  [SERV  ] Service engine 'corosync_quorum' failed to load for reason
    'configuration error: nodelist or quorum.expected_votes must be configured!'
......................

The previous error may be because the hostname of the node could...