Polling sensors settings in Nagios

Methods of survey items

Master module snmp poll to Nagios can be produced in two main ways:

1) Individual polling of each sensor: each sensor is a Nagios service, service status is determined as the state of concrete sensor;

2) Tabular polling of sensors: all sensors of some master-module are polled with Nagios, service status is determined by the aggregation state of all respondents sensors;

Setup individual polling of each sensor in Nagios

To configure Nagios polling of some sensor is necessary to make the following changes in the configuration files:

Add nagios/ objects settings subdirectory file schosts.cfg:

schosts.cfg

###############################################################################
# SCHOSTS.CFG - SAMPLE OBJECT CONFIG FILE FOR MONITORING SC DEVICES
#
#
# NOTE: This config file is intended to serve as an *extremely* simple 
#       example of how you can create configuration entries to monitor
#       the SC device.
#
###############################################################################

###############################################################################
###############################################################################
#
# HOST DEFINITION
#
###############################################################################
###############################################################################

# SC devices hosts template
define host{
       name sc-host
       use  generic-host
       max_check_attempts 10
       contact_groups admins
       action_url /pnp4nagios/graph?host=$HOSTNAME$	       ; for pnp4 graphic tool loading
       notes_url http://$HOSTADDRESS$                      ; for SC device web-ui loading
}

# SC devices hosts list
define host{
       use                     sc-host
       host_name               test193
       alias                   Local EMS
       address                 192.168.0.193
}

define host{
       use                     sc-host
       host_name               test194
       alias                   Local EMS
       address                 192.168.0.194
}

###############################################################################
###############################################################################
#
# HOST GROUP DEFINITION
#
###############################################################################
###############################################################################

# Define an optional hostgroup for Linux machines
define hostgroup{
        hostgroup_name  sc-hosts               ; The name of the hostgroup
        alias           SC hosts group         ; Long name of the group
        members         test193, test194       ; Comma separated list of hosts that belong to this group
}

###############################################################################
###############################################################################
#
# SERVICE DEFINITIONS
#
###############################################################################
###############################################################################


# Define a service to "ping" the local machine
define service{
        use                             generic-service                   ; Name of service template to use
        hostgroup_name                  sc-hosts
        service_description             PING;
        check_command                   check_ping!200.0,20%!600.0,60%    ; The command used to monitor the service
        normal_check_interval           5                                 ; Check the service every 5 minutes under normal conditions
        retry_check_interval            1                                 ; Re-check the service every minute until its final/hard state is determined
        process_perf_data               1
}

# SNMP Table of Elements for Sky Control devices  
define service{
        use                             generic-service    
        hostgroup_name                  sc-hosts
        contact_groups                  admins
        service_description             Sky Control Element Service 
        check_command                   check_snmp_vutlan! -C read -i 203001
        normal_check_interval           1
        retry_check_interval            1
        process_perf_data               1
}

##
# Scalar parse example
##
# UpTime
define service{
    use                         generic-service    
    hostgroup_name              sc-hosts
    service_description         UPTIME
    check_command check_snmp! -H $HOSTADDRESS$ -C read -o .1.3.6.1.2.1.1.3.0 -l "Uptime is"
}

# Internal Temperature
define service{
    use                         generic-service    
    hostgroup_name              sc-hosts
    service_description         Internal Temperature
    check_command check_snmp! -H $HOSTADDRESS$ -C read -o .1.3.6.1.4.1.39052.1.3.1.9.201001 -l "Internal Temperature"
}

Originally created host template for the master module (lines 19-27).
Create two hosts on the basis of this template (lines 19-27).
Hosts included in the host group (lines 52-57).
For a group of hosts specified services (lines 68-108).

PING - hosts ping services (lines 68-78);
Element Service - an exploded poll (lines 80-90);

UPTIME - scalar snmp sample survey, host uptime (lines 96-101);

Internal Temperature - SNMP table element sample survey (lines 103-108), the current value of the built-in master module temperature sensor, can be used to calculate directly a Nagios service status

Connect schosts.cfg file to the main configuration nagios.cfg
nagios.cfg
```
 cfg_file=/etc/nagios/objects/schosts.cfg
```
install Vutlan plugin for Element Service.
1) Download the plugin: check_vutlan.pl;
2) Put the plugin in the Nagios plugin directory;
3) Register plugin in objects/command.cfg.
objects/command.cfg
```
 define command {
        command_name check_snmp_vutlan
        command_line $USER1$/check_vutlan.pl -H $HOSTADDRESS$ $ARG1$
}
```
4) make sure that the plugin use correct path to the Nagios plugins directory:
snmp-graph.properties
```
 use lib "/usr/lib64/nagios/plugins";
```

Setup tabular polling of sensors in Nagios

It is necessary to make the following changes in the configuration files to configure the polling table of elements in Nagios:

Modify hosts.cfg file (see above is a complete example of creating the file above)

schosts.cfg

# SNMP Table of Elements for Vutlan devices  
define service{
        use                             generic-service    
        # host_name                     test190
        hostgroup_name                  sc-hosts
        service_description             Sky Control Table of Elements Service 
        check_command                   check_snmp_vutlan_table! -C read
        normal_check_interval           1
        retry_check_interval            1
        process_perf_data               1
}

Created check_snmp_sky_control table check service for a group of hosts sc-hosts

Test, that schosts.cfg file is connected to nagios.cfg main configuration
nagios.cfg
```
 cfg_file=/etc/nagios/objects/schosts.cfg
```
Install the plugin for Table of Elements Service.
1) Download the plugin: check_vutlan_table.pl;
2) Put a plugin in Nagios plugins directory;
3) Register plugin in objects/command.cfg.
objects/command.cfg
```
define command {
        command_name check_snmp_vutlan_table
        command_line $USER1$/check_vutlan_table.pl -H $HOSTADDRESS$ $ARG1$
}
```
4) make sure that the plugin use correct path to the Nagios plugins directory:
snmp-graph.properties
```
 use lib "/usr/lib64/nagios/plugins";
```
This plugin generates CRITICAL, if at least one element in a state of alarm, and WARNING, if at at least one element in the state WARNING
This plugin generates performance data only for sensors that have the value field makes sense (ie for sensors with analog or digital outputs)

Details about working with Nagios in official documentation: http://library.nagios.com/library/products/nagioscore/manuals/