Book Image

CentOS High Performance

By : Gabriel Cánepa
Book Image

CentOS High Performance

By: Gabriel Cánepa

Overview of this book

CentOS is the enterprise level Linux OS, which is 100% binary compatible to Red Hat Enterprise Linux (RHEL). It acts as a free alternative to RedHat's commercial Linux offering, with only a change in the branding. A high performance cluster consists in a group of computers that work together as one set parallel, hence minimizing or eliminating the downtime of critical services and enhancing the performance of the application. Starting with the basic principles of clustering, you will learn the necessary steps to install a cluster with two CentOS 7 servers. We will then set up and configure the basic required network infrastructure and clustering services. Further, you will learn how to take a proactive approach to the split-brain issue by configuring the failover and fencing of the cluster as a whole and the quorum of each node individually. Further, we will be setting up HAC and HPC clusters as a web server and a database server. You will also master the art of monitoring performance and availability, identifying bottlenecks, and exploring troubleshooting techniques. At the end of the book, you’ll review performance-tuning techniques for the recently installed cluster, test performance using a payload simulation, and learn the necessary skills to ensure that the systems, and the corresponding resources and services, are being utilized to their best capacity.
Table of Contents (13 chapters)
CentOS High Performance
About the Author
About the Reviewers

Fencing – isolating the malfunctioning nodes

As the number of nodes in a cluster increases, its availability increases, but so does the chance of one of them failing at some point. This failure event, whether serious or not, suggests that we must secure a way to isolate the malfunctioning node from the cluster in order for it to fully release its processing tasks to the rest of the cluster. Think of what an erratic node can cause in a shared storage cluster—data corruption would inevitably occur. The word malfunctioning, in this context, means not only what it suggests in the typical usage of the English language (something that is not working properly), but also a node, which also includes the resources started on it, whose state cannot be determined by the cluster for whatever reason.

This is where the term fencing comes into play. By definition, cluster fencing is the process of isolating, or separating, a node from using its resources or starting services, which it should not have access...