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

Configuring the web server as a cluster resource

You will recall from when we configured the virtual IP in Chapter 2, Installing Cluster Services and Configuring Network Components, and when we added replicated storage earlier during this chapter that we must indicate a way for PCS to check on a periodic basis whether the resource is available or not.

In this case, we will use the server status page (http://node0[1-2]/server-status), which is the preferred Apache web page as it provides information about how well the server will be performing PCS will query this page once per minute. This is accomplished by creating a file named status.conf inside /etc/httpd/conf.d on both nodes:

<Location /server-status>
  SetHandler server-status
  Order deny,allow
  Deny from all
  Allow from

Then, with the following command, we will add Apache as a cluster resource. The status of the resource will be checked by PCS once every minute:

pcs resource create webserver ocf:heartbeat...