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

Mounting the DRBD resource and using it with Apache

Before using the DRBD resource, you must define a filesystem on it and mount it on a local directory. We will use Apache's document root directory (/var/www/html), but given the case, you could use a virtual host directory as well. As we did earlier, we will add these changes in a configuration file, step by step, and we will push it to the running CIB later on node01 (or whatever the DC is).

To begin, create a new configuration file named fs_dbrd0_cfg (feel free to change the name if you want):

pcs cluster cib fs_drbd0_cfg

Next, we'll create the filesystem resource itself (again, change the variable values if needed). This is another special type of resource provided out of the box:

pcs -f fs_drbd0_cfg resource create web_fs Filesystem device="/dev/drbd0" directory="/var/www/html" fstype="ext4"

It indicates that the filesystem should always be available on the master DRBD resource:

pcs -f fs_drbd0_cfg constraint colocation add web_fs with...