How to Configure Remote System for Nagios Monitoring

# Ubuntu/Debian
$ sudo apt-get install wget build-essential openssl libssl-dev

$ useradd nagios
$ groupadd nagcmd
$ usermod -a -G nagcmd nagios
$ usermod -a -G nagios,nagcmd www-data

$ cd /tmp
$ wget http://nagios-plugins.org/download/nagios-plugins-2.1.2.tar.gz
$ wget https://github.com/NagiosEnterprises/nrpe/archive/3.0.tar.gz

$ tar zxvf nagios-plugins-2.1.2.tar.gz
$ tar zxvf 3.0.tar.gz

$ cd /tmp/nagios-plugins-2.1.2
$ ./configure --with-nagios-user=nagios --with-nagios-group=nagios --with-openssl --with-ping-command=ping
$ make
$ make install

$ cd /tmp/nrpe-3.0/
$ ./configure
$ make all
$ make install
$ make install-config
$ make install-init

$ service nagios restart
$ service nrpe restart

$ /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1
NRPE vnrpe-3.0

$ mv /usr/local/nagios/etc/nrpe.cfg /usr/local/nagios/etc/nrpe.cfg.bak
$ vim /usr/local/nagios/etc/nrpe.cfg log_facility=daemon
pid_file=/usr/local/nagios/var/nrpe.pid
server_port=5666
nrpe_user=nagios
nrpe_group=nagios
allowed_hosts=127.0.0.1
dont_blame_nrpe=0
allow_bash_command_substitution=0
debug=0
command_timeout=60
connection_timeout=300

command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10
command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
command[check_hda1]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /
command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/usr/local/nagios/libexec/check_procs -w 150 -c 200
command[check_memory]=/usr/local/nagios/libexec/check_free_mem -w 20 -c 10 -W 5 -C 10
command[check_nginx]=/usr/local/nagios/libexec/check_nginx.sh -H 127.0.0.1 -p 80 -s nginx_status -N
command[check_php]=/usr/local/nagios/libexec/check_phpfpm_status.pl -H 127.0.0.1 -u /status
command[check_mysql]=/usr/local/nagios/libexec/check_mysqld.pl -u root -p eadgwulm -T -a uptime,threads_connected,questions,slow_queries,open_tables -A threads_running,innodb_row_lock_time_avg,show global status  -w ",,,," -c ",,,,1000"

$ wget -O /usr/local/nagios/libexec/check_free_mem https://gist.githubusercontent.com/MiteshShah/65dad7fa814a31d5a8a5d7bc7716c079/raw/5c2693fedfda4eda46e71b93db7c1dcf8db0f2aa/check_free_mem
$ chmod a+x /usr/local/nagios/libexec/check_free_mem

$ wget -O /usr/local/nagios/libexec/check_nginx.sh https://gist.githubusercontent.com/MiteshShah/49279e58a73ff76f34f294dfce5af92d/raw/b00f77a79b6e89eb3c085142ff665af750873fec/check_nginx.sh
$ chmod a+x /usr/local/nagios/libexec/check_nginx.sh

$ wget -O /usr/local/nagios/libexec/check_phpfpm_status.pl https://gist.githubusercontent.com/MiteshShah/c5f23b253cb439030e5db2db1c6f4eda/raw/d286c86ee38e962e28dae9f121e983d5be7216c3/check_phpfpm_status.pl
$ chmod a+x /usr/local/nagios/libexec/check_phpfpm_status.pl

$ wget -O /usr/local/nagios/libexec/check_mysqld.pl https://gist.githubusercontent.com/MiteshShah/e4ca2ddfe0e87344f94f79b8ae6895f7/raw/050857339623f33275657b5cebc4bb2f6f0587a8/check_mysqld.pl
$ chmod a+x /usr/local/nagios/libexec/check_mysqld.pl

$ service nrpe restart

$ wget -O /etc/nginx/sites-available/status.conf https://gist.githubusercontent.com/MiteshShah/38591a384c426a63ec3b002ac0208801/raw/7cbf2cfafe142b1e048594ed72ed9a5b3dc31f09/status.conf
$ ln -s /etc/nginx/sites-available/status.conf /etc/nginx/sites-enabled/
$ nginx -t && service nginx restart