Nagios on Centos 7.x behind Nginx

Nagios is an open-source monitoring tool, can be deployed on Ubuntu, centos/rhel machines. In this tutorial, we will be deploying Nagios Core on Centos 7.4 cloud vm hosted at Google Cloud Platform, and run it behind Nginx web server.

Guide:
Step-1: Creating a Cloud Instance on GCP [ Google Cloud Platform ], following image illustrates building a Centos 7.x image

Centos 7 VM creation on Google Cloud PlatformStep-2: Following is the image which shows the instance details

GCP Instance details

Step-3: Adding the DNS and settings FQDN on cloud flareDNS and FQDN Settings on cloudflare

Step-4: Adding the DNS and settings FQDN on vm instance

$ sudo vi /etc/hosts

IPV4_ADDRESS FQDN SHORT_HOSTNAME

Step-5: Verifying FQDN

$ hostname

$ hostname -i

$ hostname -f

Step-6: Setting Locale

$ sudo timedatectl set-timezone Asia/Kolkata

Step-7: Set SELinux in permissive mode

$ sudo su -

$ setenforce 0

Step-8: Install Dev Tools, PHP, Nginx

$ sudo yum install nginx php php-fpm php-common gcc glibc glibc-common gd gd-devel make net-snmp unzip -y

$ sudo yum groupinstall 'Development Tools' -y

Step-9: Nginx – Nagios Configuration

$ cd /etc/nginx/conf.d

$ sudo vi nagios.conf

server {

    listen 80;

    server_name nagios.yebbare.com;

    access_log /var/log/nginx/nagios-access.log;

    error_log /var/log/nginx/nagios-error.log info;

    root /usr/local/nagios/share;

    index index.php;

    auth_basic "Nagios Restricted Access";

    auth_basic_user_file /usr/local/nagios/passwd;

    location /stylesheets {

        alias /usr/local/nagios/share/stylesheets;

    }

    location ~ .cgi$ {

        root /usr/local/nagios/sbin/;

        include fastcgi_params;

        rewrite ^/nagios/cgi-bin/(.*).cgi /$1.cgi break;

        fastcgi_param AUTH_USER $remote_user;

        fastcgi_param REMOTE_USER $remote_user;

        fastcgi_pass unix:/var/run/fcgiwrap.socket;

        fastcgi_param SCRIPT_FILENAME /usr/local/nagios/sbin/$fastcgi_script_name;

        fastcgi_param PATH_INFO $fastcgi_script_name;

    }

    location ~ .php$ {

        include fastcgi_params;

        fastcgi_pass unix:/var/run/php-fpm/nagios.socket;

        fastcgi_index index.php;

        fastcgi_param SCRIPT_FILENAME /usr/local/nagios/share$fastcgi_script_name;

        fastcgi_param PATH_INFO $fastcgi_script_name;

    }

    

    location ~ (.*.(ogg|ogv|svg|svgz|eot|otf|woff|mp4|ttf|rss|atom|jpg|jpeg|gif|png|ico|zip|tgz|gz|rar|bz2|doc|xls|exe|ppt|tar|mid|midi|wav|bmp|rtf))$ {

        root /usr/local/nagios/share/;

        rewrite ^/nagios/(.*) /$1 break;

        access_log off; expires max;

    }

}

Step-10: Firewall Configuration

sudo firewall-cmd --permanent --add-port=80/tcp --zone=public

sudo firewall-cmd --reload

Step-11: Creating User

useradd nagios

usermod -aG nagios nginx

Step-12: create nagios.conf for PHP-FPM

sudo vi /etc/php-fpm.d/nagios.conf

[nagios]

listen = /var/run/php-fpm/nagios.socket

listen.owner = nginx

listen.group = nginx

listen.mode=0660

listen.allowed_clients = 127.0.0.1

user = nagios

group = nagios

pm = dynamic

pm.max_children = 50

pm.start_servers = 5

pm.min_spare_servers = 5

pm.max_spare_servers = 35

slowlog = /var/log/php-fpm/www-slow.log

php_flag[display_errors] = on

php_admin_value[error_log] = /var/log/php-fpm/nagios-error.log

php_admin_flag[log_errors] = on

php_value[session.save_handler] = files

php_value[session.save_path] = /var/lib/php/session

Step-13: Restarting PHP-FPM and Enabling at start-up

sudo systemctl restart php-fpm

sudo systemctl enable php-fpm

Step-14: Download Nagios Core

wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-4.3.4.tar.gz

Step-15: Extracting the Binaries

tar zxf nagios-4.3.4.tar.gz

cd nagios-4.3.4

Step-16: Compiling the binaries and installing Nagios

sudo su -

cd nagios-4.3.4

./configure

make all

make install

make install-init

make install-config

make install-commandmode

make install-webconf

Step-17: Verifying Nagios Configuration

/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Step-18: Installing Extra Plugins

yum install nagios-plugins-all -y

Step-19: creating soft link for new pluginas and also remove the default plugins

rm -rf /usr/local/nagios/libexec

ln -s /usr/lib64/nagios/plugins /usr/local/nagios/libexec

chown -R nagios:nagios /usr/local/nagios/libexec

Step-20: Start Nagios and Enable nagios for startup at boot

systemctl start nagios

systemctl enable nagios

Step-21: Creating password for nagiosadmin user

htpasswd -c /usr/local/nagios/passwd nagiosadmin

Step-22: Creating directory for user and creating links

mkdir /usr/local/nagios/share/nagios

cd /usr/local/nagios/share/nagios/

ln -s /usr/local/nagios/share/stylesheets/ stylesheets

ln -s /usr/local/nagios/share/js js

Step-23: Installing spawn-fcgi

yum install fcgi-devel spawn-fcgi -y

Step-24: Installing fcgiwrap and installing by compiling binaries

cd /usr/local/src/

git clone https://github.com/gnosek/fcgiwrap.git

cd fcgiwrap

autoreconf -i

./configure

make

make install

Step-25: Adding the spawn-fcgi configuration

vim /etc/sysconfig/spawn-fcgi

FCGI_SOCKET=/var/run/fcgiwrap.socket

FCGI_PROGRAM=/usr/local/sbin/fcgiwrap

FCGI_USER=nginx

FCGI_GROUP=nginx

FCGI_EXTRA_OPTIONS="-M 0700"

OPTIONS="-u $FCGI_USER -g $FCGI_GROUP -s $FCGI_SOCKET -S $FCGI_EXTRA_OPTIONS -F 1 -P /var/run/spawn-fcgi.pid -- $FCGI_PROGRAM"

Step-26: Starting and Enabling Spawn-fcgi

systemctl start spawn-cgi

systemctl enable spawn-cgi