4 Descoberta de OIDs SNMP

Vista general

En aquesta secció farem un descoberta SNMP en un commutador.

Aquest mètode de descoberta d'OID SNMP és compatible des del servidor/proxy Zabbix 6.4.

Prototips d'elements, triggers, gràfics

Els prototips d'elements s'han de crear com a prototips d'elements dependents, emprant macros de la regla de descoberta.

Els elements dependents obtindran els seus valors de l'element principal walk[]. Per tant, no caldrà que cada element descobert consulti el dispositiu SNMP de manera independent.

També es poden crear prototips de trigger i gràfic emprant macros de la regla de descoberta.

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.

Entitats descobertes

Quan el servidor s'executi, crearà elements reals dependents, triggers i gràfics basats en els valors que retorna la regla de descoberta SNMP.