nagios.sh

# disable selinux

# fix/disable iptables

#################
# Nagios Server #
#################

yum install nagios nagios-plugins-all nagios-plugins-nrpe nrpe -y

chkconfig nagios on
chkconfig nrpe on
chkconfig httpd on

htpasswd -c /etc/nagios/passwd nagiosadmin

vim /etc/nagios/nagios.cfg
# uncomment this line
cfg_dir=/etc/nagios/servers

# create directory
mkdir /etc/nagios/servers

# set the following to /etc/nagios/objects/commands.cfg

vim /etc/nagios/objects/commands.cfg

define command {
     command_name check_nrpe
     command_line /usr/lib64/nagios/plugins/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
        }

# configure client on nagios server
vim /etc/nagios/conf.d/server1.cfg

define host {
        use                     linux-server
        host_name               server1
        address                 10.104.3.129
        }

define service {
        use                             generic-service
        host_name                       server1
        service_description             PING
        check_command                   check_ping!100.0,20%!500.0,60%
        }

define service {
        use                             generic-service
        host_name                       server1
        service_description             SSH
        check_command                   check_ssh
        notifications_enabled           0
        }

define service {
        use                             generic-service
        host_name                       server1
        service_description             Current Load
        check_command                   check_local_load!5.0,4.0,3.0!10.0,6.0,4.0
        }

define service{
        use                             generic-service
        host_name                       server1
        service_description             Root Partition
        check_command                   check_nrpe!check_disk
        }

define service{
        use                             generic-service
        host_name                       server1
        service_description             Total Processes
        check_command                   check_nrpe!check_procs
        }

touch /var/www/html/index.html
chmod 755 /var/www/html/index.html

service httpd start
service nagios start

#################
# Nagios Client #
#################

yum install nrpe nagios-plugins-all nagios-plugins-nrpe -y

# modify nrpe config file
vim /etc/nagios/nrpe.cfg

cat > /etc/nagios/nrpe.cfg <<EOF
log_facility=daemon
pid_file=/var/run/nrpe/nrpe.pid
server_port=5666
nrpe_user=nrpe
nrpe_group=nrpe
allowed_hosts=10.104.3.128
dont_blame_nrpe=1
allow_bash_command_substitution=0
debug=0
command_timeout=60
connection_timeout=300
include_dir=/etc/nrpe.d/
command[check_users]=/usr/lib64/nagios/plugins/check_users -w 5 -c 10
command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20
command[check_disk]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /
command[check_procs]=/usr/lib64/nagios/plugins/check_procs -w 150 -c 200 -s RSZDT
command[check_zombie_procs]=/usr/lib64/nagios/plugins/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/usr/lib64/nagios/plugins/check_procs -w 150 -c 200
EOF

chkconfig nrpe on
service nrpe start

# gotchas

1. If HTTP service on localhost is showing warning, create index.html file and set the right permission
touch /var/www/html/index.html
chmod 755 /var/www/html/index.html

2. PING, SSH might take a little longer to get green

3. Check NRPE connectivity, /usr/lib64/nagios/plugins/check_nrpe -H 10.104.3.129