Dynamic OID

[northboys]

Hi guys,
how can I add a dynamic OID in the configuration file, I have a case when I want to take the IP of a device, the oid is mixed with the IP, how do I avoid having to add the oid one by one when there are many devices to be monitored?

for example:
using snmpwalk

iso.3.6.1.2.1.3.1.1.1.8.1.192.168.0.74 = INTEGER: 8
iso.3.6.1.2.1.3.1.1.2.8.1.192.168.0.74 = Hex-STRING: 00 01 02 03 04 CC
iso.3.6.1.2.1.3.1.1.3.8.1.192.168.0.74 = IpAddress: 192.168.0.74

is it possible to add OID like this

  metrics:
    - name: mClientIPaddr
      oid: "1.3.6.1.2.1.3.1.1.2.8.1.*"
      type: DisplayString

[SuperQ]

Those are different OIDs with different indexes. In fact, it looks like that is just part of atTable which comes from RFC1213-MIB.

The only difficulty here is that RFC1213-MIB has conflicts with the newer SNMPv2-TC MIB, so you need a separate set of MIBs to avoid those conflicts.

Here's what I get when I setup a generator.yml:

modules:
  atTable:
    walk:
      - atTable

When I generate that with the RFC1213-MIB in my MIBDIRS I get this snmp.yml configuration:

# WARNING: This file was auto-generated using snmp_exporter generator, manual changes will be lost.
modules:
  atTable:
    walk:
    - 1.3.6.1.2.1.3.1
    metrics:
    - name: atIfIndex
      oid: 1.3.6.1.2.1.3.1.1.1
      type: gauge
      help: The interface on which this entry's equivalence is effective - 1.3.6.1.2.1.3.1.1.1
      indexes:
      - labelname: atIfIndex
        type: gauge
      - labelname: atNetAddress
        type: InetAddressIPv4
    - name: atPhysAddress
      oid: 1.3.6.1.2.1.3.1.1.2
      type: PhysAddress48
      help: The media-dependent `physical' address - 1.3.6.1.2.1.3.1.1.2
      indexes:
      - labelname: atIfIndex
        type: gauge
      - labelname: atNetAddress
        type: InetAddressIPv4
    - name: atNetAddress
      oid: 1.3.6.1.2.1.3.1.1.3
      type: InetAddressIPv4
      help: The NetworkAddress (e.g., the IP address) corresponding to the media-dependent
        `physical' address. - 1.3.6.1.2.1.3.1.1.3
      indexes:
      - labelname: atIfIndex
        type: gauge
      - labelname: atNetAddress
        type: InetAddressIPv4

If you read the atEntry definition in the MIB you'll see how the INDEX is defined:

atEntry OBJECT-TYPE
    SYNTAX  AtEntry
    ACCESS  not-accessible
    STATUS  deprecated
    DESCRIPTION
            "Each entry contains one NetworkAddress to
            `physical' address equivalence."
    INDEX   { atIfIndex,
              atNetAddress }
    ::= { atTable 1 }

In this case, the index is actually two parts. The single octet atIfIndex and the 4 octet atNetAddress

You can see how things are broken up. The iso.3.6.1.2.1.3.1.1.1 is the actual metric entry. The .8. is the index number, and the .1.192.168.0.74 is an atNetAddress, which is defined as a RFC1155-SMI NetworkAddress which is defined as an internet IpAddress, which is 1 plus 4 octets of an IPv4 address.

Most of this MIB is marked deprecated, I think there are newer OIDs that should have the same data. But I don't remember off the top of my head what those are.