Monitoring with Nagios and Nginx
5 minute read
Nagios provides enterprise-class Open Source IT monitoring, network monitoring, server and applications monitoring.
We’ll cover Linux (Ubuntu) Server Monitoring.
Update your system.
apt update and optionally upgrade using apt upgrade
Install the required dependencies using:
apt-get install -y build-essential dos2unix gcc git libmcrypt4 libpcre3-dev ntp unzip make python2.7-dev python-pip re2c supervisor unattended-upgrades whois vim libnotify-bin pv cifs-utils
Run this command to Add these missing software sources to your distro:
apt-get install -y software-properties-common curl
apt-add-repository ppa:ondrej/php -y
apt-add-repository ppa:nginx/development -y
install PHP Specific Dependencies using :
apt-get install php7.1-cli php7.1-dev \
php7.1-pgsql php7.1-sqlite3 php7.1-gd \
php7.1-curl php7.1-memcached \
php7.1-imap php7.1-mysql php7.1-mbstring \
php7.1-xml php7.1-zip php7.1-bcmath php7.1-soap \
php7.1-intl php7.1-readline php-xdebug
Set these PHP Module variables:
sudo sed -i "s/error_reporting = .*/error_reporting = E_ALL/" /etc/php/7.1/cli/php.ini
sudo sed -i "s/display_errors = .*/display_errors = On/" /etc/php/7.1/cli/php.ini
sudo sed -i "s/memory_limit = .*/memory_limit = 512M/" /etc/php/7.1/cli/php.ini
sudo sed -i "s/;date.timezone.*/date.timezone = UTC/" /etc/php/7.1/cli/php.ini
Install PHP-FPM and NGINX apt-get install nginx php7.1-fpm
Setup Some PHP-FPM Options
echo "xdebug.remote_enable = 1" >> /etc/php/7.1/mods-available/xdebug.ini
echo "xdebug.remote_connect_back = 1" >> /etc/php/7.1/mods-available/xdebug.ini
echo "xdebug.remote_port = 9000" >> /etc/php/7.1/mods-available/xdebug.ini
echo "xdebug.max_nesting_level = 512" >> /etc/php/7.1/mods-available/xdebug.ini
echo "opcache.revalidate_freq = 0" >> /etc/php/7.1/mods-available/opcache.ini
sed -i "s/error_reporting = .*/error_reporting = E_ALL/" /etc/php/7.2/fpm/php.ini
sed -i "s/display_errors = .*/display_errors = On/" /etc/php/7.1/fpm/php.ini
sed -i "s/;cgi.fix_pathinfo=1/cgi.fix_pathinfo=0/" /etc/php/7.1/fpm/php.ini
sed -i "s/memory_limit = .*/memory_limit = 512M/" /etc/php/7.1/fpm/php.ini
sed -i "s/upload_max_filesize = .*/upload_max_filesize = 100M/" /etc/php/7.1/fpm/php.ini
sed -i "s/post_max_size = .*/post_max_size = 100M/" /etc/php/7.1/fpm/php.ini
sed -i "s/;date.timezone.*/date.timezone = UTC/" /etc/php/7.1/fpm/php.ini
Disable XDebug On The CLI
sudo phpdismod -s cli xdebug
Copy fastcgi_params to Nginx because they broke it on the PPA
cat > /etc/nginx/fastcgi_params << EOF
fastcgi_param QUERY_STRING \$query_string;
fastcgi_param REQUEST_METHOD \$request_method;
fastcgi_param CONTENT_TYPE \$content_type;
fastcgi_param CONTENT_LENGTH \$content_length;
fastcgi_param SCRIPT_FILENAME \$request_filename;
fastcgi_param SCRIPT_NAME \$fastcgi_script_name;
fastcgi_param REQUEST_URI \$request_uri;
fastcgi_param DOCUMENT_URI \$document_uri;
fastcgi_param DOCUMENT_ROOT \$document_root;
fastcgi_param SERVER_PROTOCOL \$server_protocol;
fastcgi_param GATEWAY_INTERFACE CGI/1.1;
fastcgi_param SERVER_SOFTWARE nginx/\$nginx_version;
fastcgi_param REMOTE_ADDR \$remote_addr;
fastcgi_param REMOTE_PORT \$remote_port;
fastcgi_param SERVER_ADDR \$server_addr;
fastcgi_param SERVER_PORT \$server_port;
fastcgi_param SERVER_NAME \$server_name;
fastcgi_param HTTPS \$https if_not_empty;
fastcgi_param REDIRECT_STATUS 200;
EOF
Set The Nginx & PHP-FPM User
sed -i "s/user www-data;/user www-data;/" /etc/nginx/nginx.conf
sed -i "s/# server_names_hash_bucket_size.*/server_names_hash_bucket_size 64;/" /etc/nginx/nginx.conf
sed -i "s/user = www-data/user = www-data/" /etc/php/7.1/fpm/pool.d/www.conf
sed -i "s/group = www-data/group = www-data/" /etc/php/7.1/fpm/pool.d/www.conf
sed -i "s/listen\.owner.*/listen.owner = www-data/" /etc/php/7.1/fpm/pool.d/www.conf
sed -i "s/listen\.group.*/listen.group = www-data/" /etc/php/7.1/fpm/pool.d/www.conf
sed -i "s/;listen\.mode.*/listen.mode = 0666/" /etc/php/7.1/fpm/pool.d/www.conf
Create Nagios User
useradd nagios
usermod -a -G nagios www-data
Download Nagios Using:
wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.3.4.tar.gz
Extract the download using:
tar -zxvf nagios-4.3.4.tar.gz
Go into the extracted folder
cd nagios-4.3.4
configure the installer using:
./configure --with-nagios-group=nagios --with-command-group=www-data --with-mail=/usr/sbin/sendmail
If all runs fine. Execute: ```make all``
If that runs successuflly without any issues/errors and the configuration console output appears OK with you, then proceed to run the commands below:
make install
make install-commandmode
make install-init
make install-config
Enable the Nagios service using:
systemctl enable nagios.service
Nagios Plugins
Download using:
wget https://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
Extract Using:
tar -zxvf nagios-plugins-2.2.1.tar.gz && cd nagios-plugins-2.2.1
Configure Using:
./configure --with-nagios-user=nagios --with-nagios-group=www-data --with-openssl
Compile Using:
make
Install Using:
make install
NRPE
Download to your local machine from: http://downloads.sourceforge.net/project/nagios/nrpe-2.x/nrpe-3.1.1/nrpe-3.2.1.tar.gz
Push to remote machine using:
scp -P port_number Downloads/nrpe-3.2.1.tar.gz [email protected]:/var/www/
where port_number is the ssh port number of your server. Default is 22
In your remote server, Extract the newly uploaded file using:
tar -zxvf nrpe-3.2.1.tar.gz && cd nrpe-3.2.1
Configure it Using:
./configure --enable-command-args --with-nagios-user=nagios --with-nagios-group=www-data --with-ssl=/usr/bin/openssl --with-ssl-lib=/usr/lib/x86_64-linux-gnu --with-need-dh=no
dh sometimes causes config issues/errors so i set the glag --with-need-dh=no
Compile and Install Using:
make install
make install-init
make install-config
Enalbe NRPE Service:
systemctl enable nrpe.service
Configure Nagios
Open Config in your favourite terminal editor. I use vim:
vim /usr/local/nagios/etc/nagios.cfg
Uncomment #cfg_dir=/usr/local/nagios/etc/servers by Removing the # symbol
Create the direcory where we’ll put all our server config files.
mkdir -p /usr/local/nagios/etc/servers
Configure Nagios Admin User
Install apache2-utils using:
apt get install apache2-utils
Create nagios admin user account using:
sudo htpasswd -b -c /usr/local/nagios/etc/.htpasswd nagiosadmin nagiospassword
-b enables the use of password from commandline rather than prompting for it.
-c creates a new file. Overwrites any existing in the same path.
Add the following setting to your Nginx Web server Config in /etc/nginx/sites-available
auth_basic "Private";
auth_basic_user_file /usr/local/nagios/etc/.htpasswd;
Configure Nagios Contact
Open the contact config file in your editor:
vim /usr/local/nagios/etc/objects/contacts.cfg
Change the default contact address to your email address
email nagios@localhost ; <<***** CHANGE THIS TO YOUR EMAIL ADDRESS ******
Configure NRPE Command
Open the commands config file in your editor:
vim /usr/local/nagios/etc/objects/commands.cfg
Append the following to the end of the file.
define command {
command_name check_nrpe
command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
}
This allows you to see check_nrpe command in your Nagios service definition.
NGINX Config
Ensure that your Nginx site config file in /etc/nginx/sites-available/ looks like this:
server {
listen 443;
listen [::]:443;
# force https-redirect
ssl on;
ssl_certificate /etc/letsencrypt/live/eopio.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/eopio.com/privkey.pem;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
add_header Strict-Transport-Security "max-age=31536000";
server_name localhost;
root /var/www/ghost/system/nginx-root;
index index.php index.html;
location / {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://127.0.0.1:2368;
}
location ~ /.well-known {
allow all;
# root /var/www/ghost/system/nginx-root;
default_type "text/plain";
}
location ~ /js {
allow all;
root /var/www/ghost/system/nginx-root;
default_type "text/javascript";
}
location /apple-app-site-association {
default_type application/json;
}
location /nagios {
alias /usr/local/nagios/share;
allow all;
auth_basic "Private";
auth_basic_user_file /usr/local/nagios/etc/.htpasswd;
location ~ \.php$ {
include snippets/fastcgi-php.conf;
fastcgi_param SCRIPT_FILENAME $request_filename;
fastcgi_param AUTH_USER $remote_user;
fastcgi_param REMOTE_USER $remote_user;
fastcgi_pass unix:/run/php/php7.1-fpm.sock;
}
location ~ \.cgi$ {
root /usr/local/nagios/sbin;
rewrite ^/nagios/cgi-bin/(.*)\.cgi /$1.cgi break;
include /etc/nginx/fastcgi_params;
fastcgi_param SCRIPT_FILENAME $request_filename;
fastcgi_param AUTH_USER $remote_user;
fastcgi_param REMOTE_USER $remote_user;
fastcgi_pass unix:/var/run/fcgiwrap.socket;
}
}
location ~ ^/nagiosgraph/cgi-bin/(.*\.cgi)$ {
alias /usr/local/nagiosgraph/cgi/$1;
include /etc/nginx/fastcgi_params;
fastcgi_param SCRIPT_FILENAME $request_filename;
fastcgi_param AUTH_USER $remote_user;
fastcgi_param REMOTE_USER $remote_user;
fastcgi_pass unix:/var/run/fcgiwrap.socket;
}
location /nagiosgraph {
alias /usr/local/nagiosgraph/share;
}
location ~ \.php$ {
include snippets/fastcgi-php.conf;
fastcgi_pass unix:/run/php/php7.1-fpm.sock;
}
client_max_body_size 50m;
}
server {
listen 80;
listen [::]:80;
#
server_name eopio.com;
# rewrite ^ https://$server_name$request_uri? permanent;
#
root /var/www/ghost/system/nginx-root;
index index.html;
#
location / {
rewrite ^ https://$server_name$request_uri? permanent;
# try_files $uri $uri/ =404;
}
}
Start Nagios service
systemctl start nagios
and restart nginx
systemctl restart nginx
If the console has no output, then all is good. Otherwise, Keep Calm and read the error message.
If no errors, add nagios to startup commands:
sudo ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios
Goto your_domain/nagios e.g eopio nagios
Enter your nagios admin username and password.
Get Monitoring!
Thank you and Feel free to reach out!