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

Chapter 3. A Closer Look at High Availability

In this chapter, we will look at the components of a high-availability cluster in greater detail than we were able to do initially during Chapter 1, Cluster Basics and Installation on CentOS 7; you may want to review that chapter in order to refresh your memory before proceeding further.

In this chapter, we will cover the following topics:

  • Failover—a premier on high availability and performance

  • Fencing — isolating the malfunctioning nodes

  • Split brain — preparing to avoid inconsistencies

  • Quorum — scoring inside your cluster

  • Configuring our cluster via PCS GUI

We will set out on this chapter by asking ourselves a few questions about how to achieve high availability, and we will attempt to get our answers as we go along. In the next chapter, we will set up actual real-life examples:

  • How can we ensure an automatic failover without the need for human intervention?

  • How many nodes are needed in a cluster in order to ensure high availability in several failure...