4 Discovery of SNMP OIDs

Обзор

В этом разделе мы выполним SNMP обнаружение на коммутаторе.

Этот метод обнаружения OID SNMP поддерживается начиная с Zabbix сервера/прокси версии 6.4.

Item prototypes

The following screenshot illustrates how we can use these macros in item prototypes:

Again, creating as many item prototypes as needed:

Dynamic indexes with walk[]

Dynamic indexes (for example, interface indexes) can shift when hardware is reconfigured. To accommodate this behavior, a master SNMP walk discovery rule is created with a key such as:

walk[1.3.6.1.2.1.2.2.1.10]

After SNMP walk to JSON preprocessing, the result might resemble:

[
           {
               "{#SNMPINDEX}": "2",
               "{#VALUE}": "123456"
           },
           {
               "{#SNMPINDEX}": "3",
               "{#VALUE}": "654321"
           }
       ]

A dependent item prototype uses the {#SNMPINDEX} macro to construct the key:

net.if.in[{#SNMPINDEX}]

Preprocessing for this prototype includes "SNMP walk value" name with "1.3.6.1.2.1.2.2.1.10.{#SNMPINDEX}" OID in the Parameter field. Format: "Unchanged".

At runtime, actual items such as net.if.in[2] and net.if.in[3] are created. If a given interface index changes (for example, if the index 2 is replaced by 5 in the SNMP table), then on the next run of the discovery rule:

• The old dependent item net.if.in[2] is marked as "lost" or removed, and no new data is gathered for that item.
• A new dependent item net.if.in[5] is created, starting with an empty history.
• Historical data from net.if.in[2] is not automatically moved to net.if.in[5].

Trigger prototype example:

{Template_Interface:net.if.in[{#SNMPINDEX}].last()} > 1000000000

Graph prototype example includes items:

net.if.in[{#SNMPINDEX}]
       net.if.out[{#SNMPINDEX}]

This configuration ensures reliable monitoring of tables with dynamic indexes while minimizing SNMP traffic—only a single SNMP walk per poll cycle is required, with dependent item prototypes extracting the necessary values.

Discovered entities

When server runs, it will create real items, triggers and graphs based on the values the SNMP discovery rule returns. In the host configuration they are prefixed with an orange link to a discovery rule they come from.