Installing Nginx in CentOS/RedHat server

Nginx is an open source web server which is robust, fast and very easy to work with. It can be used to replace Apache or configured as a reverse proxy for Apache server. Nginx can also be configured to act as a load balancer.

This guide explains how to install and perform the initial configuration of Nginx Web Server on CentOS/RHEL based systems.

Nginx Repository

It is recommended to install nginx packages directly from the nginx yum repository.

To add the yum repository, create a file named /etc/yum.repos.d/nginx.repo, and paste one of the configurations below.

For CentOS :
[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=0
enabled=1

For RHEL:
[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/rhel/$releasever/$basearch/
gpgcheck=0
enabled=1

Manually replace $releasever with either “5” (for 5.x) or “6” (for 6.x), depending upon your OS version.

Installation

Install the nginx web server with yum :

# yum install nginx

Set the nginx to start at boot :

# chkconfig nginx on

Basic Configuration

Backup the configuration files :

# cp /etc/nginx/nginx.conf /etc/nginx/nginx.conf.back
# cp /etc/nginx/conf.d/default.conf /etc/nginx/conf.d/default.conf.back

Edit the nginx configuration file /etc/nginx/nginx.conf. Change the worker_processes value. It should be equal to the number of CPUs in your server.

worker_processes 1;

To list the number of CPUs, you can use the following command :

# lscpu | grep ‘^CPU(s)’

Enable compression by uncommenting the following line :

gzip on;

Save and close the file.

Edit the file /etc/nginx/conf.d/default.conf. Set the server’s name :

server_name example.com;

Save and close the file. Start Nginx :

# service nginx start

Confirming the installation

Enter the server’s name or IP address in your web-browser. If you see the following text, it means Nginx is successfully installed.

“Welcome to Nginx!”

Following are the default Nginx configuration files.

/etc/nginx/ – Nginx server configuration directory;
/etc/nginx/conf.d/ – SSL and vhost configuration directory;
/etc/nginx/nginx.conf – main configuration file;
/var/log/nginx/error.log – error logs;
/var/log/nginx/access.log – access logs;
/usr/share/nginx/html/ – Nginx default document root directory;

Following are some Nginx commands

# /etc/init.d/nginx start
# /etc/init.d/nginx stop
# /etc/init.d/nginx restart
# /etc/init.d/nginx condrestart
# /etc/init.d/nginx try-restart
# /etc/init.d/nginx force-reload
# /etc/init.d/nginx upgrade
# /etc/init.d/nginx reload
# /etc/init.d/nginx status
# /etc/init.d/nginx help
# /etc/init.d/nginx configtest