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

Monitoring the node status

As you can guess, perhaps the first thing that you always need to check is the status of each node—whether they are online or offline. Otherwise, there is little point in proceeding with further availability and performance analysis.

If you have a network management system (such as Zabbix or Nagios) server, you can easily monitor the status of your cluster members and receive alerts when they are unreachable. If not, you must come up with a supplementary solution of your own (which may not be as effective or errorproof) that you can use to detect when a node has gone offline.

One such solution is a simple bash script (we will name it, save it inside /root/scripts, and make it executable with chmod +x /root/scripts/ which will periodically ping your nodes from another host and report via an e-mail to the system administrator if one of them is offline in order for you to take appropriate action. The following shell script does just that...