On the host you have chosen to be the Nagios server, install the RPMs:
For RHEL and CentOS
yum install net-snmp net-snmp-utils php-pecl-json yum install wget httpd php net-snmp-perl perl-Net-SNMP fping nagios-3.2.3 nagios-plugins-1.4.9 hdp_mon_nagios_addons
For SLES
zypper install net-snmp zypper install wget apache2 php php-curl perl-SNMP perl-Net-SNMP fping nagios-3.2.3-2.1 nagios-plugins-1.4.9 hdp_mon_nagios_addons