Model Configuration

Model System Overview

NMIS uses device models to define how network equipment is monitored. Models specify:

SNMP OID mappings - Which OIDs to collect
Data structures - How to organize collected data
Collection definitions - What metrics to gather
Thresholds - Alert conditions
Display mappings - How data appears in UI

Model Locations

models-default/

Shipped models from Opmantek:

Pre-built vendor models - Cisco, Juniper, etc.
Protected from upgrades - Maintained by Opmantek
Base directory: /usr/local/nmis9/models-default/

From Config.nmis:38:

'directories' => {
  '<nmis_default_models>' => '<nmis_base>/models-default'
}

models-custom/

Customer-specific models:

Custom device models - Site-specific models
Model overrides - Customizations of default models
Preserved during upgrades - User changes maintained
Base directory: /usr/local/nmis9/models-custom/

From Config.nmis:40:

'directories' => {
  '<nmis_models>' => '<nmis_base>/models-custom'
}

Model Selection

NMIS automatically selects models based on:

sysObjectID - SNMP system object identifier
sysDescr - System description string
Vendor - Device manufacturer
Model - Specific device model

Model precedence:

models-custom/ (highest priority)
models-default/ (fallback)

Model Structure

Model File Format

Models are Perl hash structures:

%hash = (
  'systemHealth' => {
    'sys' => {
      'standard' => {
        'snmp' => {
          'sysDescr' => {
            'oid' => '1.3.6.1.2.1.1.1.0',
            'title' => 'Description'
          },
          'sysUpTime' => {
            'oid' => '1.3.6.1.2.1.1.3.0',
            'title' => 'Uptime',
            'calculate' => 'return func::convUpTime($r);'
          }
        }
      }
    }
  }
);

Model Components

System Health

Collects device-level metrics:

CPU utilization
Memory usage
Temperature sensors
Fan status
Power supplies

Interface Data

Collects interface metrics:

Traffic counters
Errors and discards
Utilization
Status (up/down)

Model Schema

Model-Schema.nmis defines the valid structure and data types for models.

Schema Keywords

From Model-Schema.nmis:1:

%hash = (
  'keywords' => {
    'Description' => {
      'locations' => [
        'interface/nocollect',
        'interface/collect',
        'storage/nocollect'
      ],
      'types' => ['string'],
      'special' => 1
    },
    'calculate' => {
      'types' => ['string'],
      'special' => 1
    }
  }
);

Threshold Definitions

From Model-Schema.nmis:73:

'Critical' => {
  'name' => 'Critical',
  'parents' => ['threshold'],
  'types' => ['integer', 'real'],
  'values' => ['95', '3000', '50', '98']
}

Model Policy

Model-Policy.nmis controls which data collection sections are active. From Model-Policy.nmis:44:

999 => {  # Default fallback
  systemHealth => {
    'cdp' => 'true',
    'lldp' => 'true',
    'bgpPeer' => 'true',
    'ospfNbr' => 'true',
    'entityMib' => 'true',
    'fanStatus' => 'true',
    'tempStatus' => 'true',
    'diskIOTable' => 'true'
  }
}

Policy Rules

Policies can filter by node attributes:

10 => {
  IF => {
    'node.name' => ['router1', 'router2'],
    'node.location' => '/DataCenter/'
  },
  systemHealth => {
    'bgpPeer' => 'true',
    'ospfNbr' => 'true'
  }
}

OID Mapping

SNMP OID Definition

'memoryUsed' => {
  'oid' => '1.3.6.1.4.1.9.9.48.1.1.1.5',
  'sysObjectName' => 'ciscoMemoryPoolUsed',
  'title' => 'Memory Used'
}

Indexed OIDs

For table data:

'ifDescr' => {
  'oid' => '1.3.6.1.2.1.2.2.1.2',
  'title' => 'Interface Description'
}

Data Calculations

Calculate Field

Transform collected data:

'calculate' => '$r / 1000'  # Convert to seconds

From Model-Schema.nmis:441:

'sysUpTime' => {
  'calculate' => '$r = int($r/100); $r = func::convUpTime($r);'
}

Common Calculations

Temperature conversion:

'calculate' => '${r}/10'  # Divide by 10

Percentage calculation:

'calculate' => 'CVAR1=MemoryUsed; CVAR2=MemoryTotal; return ($CVAR1/$CVAR2 * 100);'

IP address format:

'calculate' => '$r =~ s/^0x//; $r = join ".", map { hex } $r =~ /../g;'

Control Filters

Collection Control

From Model-Schema.nmis:881:

'control' => '$sysObjectName =~ /7206|6509/'

Control expressions determine if data is collected: By device type:

'control' => '$nodeType eq "router"'

By interface speed:

'control' => '$ifSpeed >= 1000000000'  # 1Gbps+

By storage type:

'control' => 'CVAR=hrStorageType; $CVAR =~ /Fixed Disk/'

NoCollect Rules

From interface collection:

'nocollect' => {
  'Description' => '^#|loopback|NO COLLECT',
  'ifOperStatus' => 'down',
  'ifType' => 'softwareLoopback'
}

Alerts and Thresholds

From Model-Schema.nmis:1250:

Alert Definition

'alerts' => {
  'ciscoMemoryPool' => {
    'memoryUtilisation' => {
      'element' => 'MemPoolName',
      'event' => 'High Memory Utilisation',
      'level' => 'Warning',
      'test' => '$r > 80',
      'value' => 'CVAR1=memUsed;CVAR2=memFree;int($CVAR1 / ($CVAR1 + $CVAR2) * 100)',
      'threshold' => {
        'Warning' => 80,
        'Minor' => 85,
        'Major' => 90,
        'Critical' => 95,
        'Fatal' => 99
      }
    }
  }
}

Threshold Levels

Normal - 0-69%
Warning - 70-79%
Minor - 80-84%
Major - 85-89%
Critical - 90-95%
Fatal - 96-100%

Common Model Types

Interface Model

'interface' => {
  'sys' => {
    'standard' => {
      'indexed' => 'true',
      'snmp' => {
        'ifIndex' => {
          'oid' => '1.3.6.1.2.1.2.2.1.1',
          'title' => 'Interface Index'
        },
        'ifDescr' => {
          'oid' => '1.3.6.1.2.1.2.2.1.2',
          'title' => 'Interface Name'
        },
        'ifSpeed' => {
          'oid' => '1.3.6.1.2.1.2.2.1.5',
          'title' => 'Interface Speed'
        }
      }
    }
  },
  'rrd' => {
    'interface' => {
      'snmp' => {
        'ifInOctets' => {
          'oid' => '1.3.6.1.2.1.2.2.1.10',
          'option' => 'counter,0:U'
        },
        'ifOutOctets' => {
          'oid' => '1.3.6.1.2.1.2.2.1.16',
          'option' => 'counter,0:U'
        }
      }
    }
  }
}

CPU Model

'rrd' => {
  'cpu' => {
    'snmp' => {
      'avgBusy5' => {
        'oid' => '1.3.6.1.4.1.9.2.1.58.0',
        'option' => 'gauge,0:100'
      }
    },
    'threshold' => 'cpu',
    'graphtype' => 'cpu'
  }
}

Memory Model

'rrd' => {
  'memory' => {
    'indexed' => 'true',
    'snmp' => {
      'memUsed' => {
        'oid' => '1.3.6.1.4.1.9.9.48.1.1.1.5',
        'option' => 'gauge,0:U'
      },
      'memFree' => {
        'oid' => '1.3.6.1.4.1.9.9.48.1.1.1.6',
        'option' => 'gauge,0:U'
      }
    }
  }
}

Creating Custom Models

1. Copy Base Model

cp /usr/local/nmis9/models-default/Model-Generic.nmis \
   /usr/local/nmis9/models-custom/Model-CustomDevice.nmis

2. Modify Model

Edit the custom model:

%hash = (
  'system' => {
    'nodeModel' => 'CustomDevice',
    'nodeVendor' => 'CustomVendor',
    'sys' => {
      'standard' => {
        'snmp' => {
          'sysObjectID' => {
            'replace' => {
              '1.3.6.1.4.1.9999' => 'CustomDevice'
            }
          }
        }
      }
    }
  }
);

3. Test Model

/usr/local/nmis9/bin/nmis-cli \
  act=update \
  node=testdevice \
  debug=true

Always test custom models on non-production nodes first. Invalid model syntax can prevent data collection.

Model Inheritance

Common Models

From Model-Schema.nmis:664:

'common-model' => {
  'values' => [
    'database',
    'threshold',
    'lldp',
    'entityMib',
    'interface',
    'Cisco-cpu',
    'Cisco-memory'
  ]
}

Models can reference common sections:

'systemHealth' => {
  'sys' => {
    'entityMib' => {
      'common-model' => 'entityMib'
    }
  }
}

Model Debugging

Enable Model Debug

/usr/local/nmis9/bin/nmis-cli \
  act=collect \
  node=router1 \
  debug=9

View Model Loading

Check which model was selected:

grep 'Loading Model' /usr/local/nmis9/logs/nmis.log

Validate Model Syntax

perl -c /usr/local/nmis9/models-custom/Model-CustomDevice.nmis

Getting Started

Core Features

Configuration

Device Models

Administration

Deployment

​Model System Overview

​Model Locations

​models-default/

​models-custom/

​Model Selection

​Model Structure

​Model File Format

​Model Components

​System Health

​Interface Data

​Model Schema

​Schema Keywords

​Threshold Definitions

​Model Policy

​Policy Rules

​OID Mapping

​SNMP OID Definition

​Indexed OIDs

​Data Calculations

​Calculate Field

​Common Calculations

​Control Filters

​Collection Control

​NoCollect Rules

​Alerts and Thresholds

​Alert Definition

​Threshold Levels

​Common Model Types

​Interface Model

​CPU Model

​Memory Model

​Creating Custom Models

​1. Copy Base Model

​2. Modify Model

​3. Test Model

​Model Inheritance

​Common Models

​Model Debugging

​Enable Model Debug

​View Model Loading

​Validate Model Syntax

​Related Documentation

Build docs developers (and LLMs) love

Model System Overview

Model Locations

models-default/

models-custom/

Model Selection

Model Structure

Model File Format

Model Components

System Health

Interface Data

Model Schema

Schema Keywords

Threshold Definitions

Model Policy

Policy Rules

OID Mapping

SNMP OID Definition

Indexed OIDs

Data Calculations

Calculate Field

Common Calculations

Control Filters

Collection Control

NoCollect Rules

Alerts and Thresholds

Alert Definition

Threshold Levels

Common Model Types

Interface Model

CPU Model

Memory Model

Creating Custom Models

1. Copy Base Model

2. Modify Model

3. Test Model

Model Inheritance

Common Models

Model Debugging

Enable Model Debug

View Model Loading

Validate Model Syntax

Related Documentation