https://github.com/andrewjswan/snmp2mqtt-addon/

mqtt:
  host: 192.168.1.5 # Optional: broker URL or IP address (default: localhost)
  port: 1884 # Optional: broker port (default: 1883 or 8883 for TLS connections)
  username: my_user # Optional: broker user (default: none)
  password: my_password # Optional: broker password (default: none)
  client_id: snmp2mqtt # Optional: client ID (default: snmp2mqtt)
  keepalive: 30 # Optional: keepalive in seconds (default: 10)
  clean: true # Optional: clean session (default: true)
  retain: true # Optional: retain (default: true)
  qos: 2 # Optional: QoS (default: 0)
  base_topic: # Optional: the base level of the topic (default: snmp2mqtt)
  host_name_as_target: true # Optional: Use the target's name instead of the host as the MQTT topic (default: false)
  ca: /cert/ca.pem # Optional: CA for TLS connection (default: none)
  cert: /cert/cert.pem # Optional: certificate for TLS connection (default: none)
  key: /cert/key.pem # Optional: private key for TLS connection (default: none)
  reject_unauthorized: true # Optional: if not false, the server certificate is verified against the list of supplied CAs. Override with caution (default: true when using TLS)

homeassistant:
  discovery: true # Optional: enable Home Assistant discovery (default: false)
  prefix: "home-assistant" # Optional: Home Assistant MQTT topic prefix (default: homeassistant)

targets_path: "/config/addons_config/snmp2mqtt/targets.yaml"

log: debug # Optional: debug, info, warning or error (default: info)

targets:
  - host: 192.168.0.2 # Required: target IP address
    name: Raspberry Pi # Optional: target name
    mac: 00:00:00:00:00:00 # Optional: mac adress
    scan_interval: 30 # Optional: fetch interval in seconds (default: 10)
    device_manufacturer: Raspberry Pi # Optional: set the device manufacturer in Home Assistant
    device_model: 3 Model B # Optional: set the device model in Home Assistant
    suggested_area: Bedroom # Optional: set the area in Home Assistant
    auth_key: password # Optional: set the auth password for SNMPv3
    auth_protocol: sha # Optional: set the auth protocol for SNMPv3, one of sha or md5
    priv_key: password # Optional: set the privilege password for SNMPv3
    priv_protocol: des # Optional: set the privilege protocol for SNMPv3, one of des, aes, aes256b or aes256r
    version: "3" # Optional: 1, 2c or 3 (default: 1)
    sensors:
      - oid: 1.3.6.1.2.1.25.1.1.0 # Required: SNMP oid
        name: Raspberry Pi Uptime # Required: sensor name
        unit_of_measurement: days # Optional: set the unit of measurement in Home Assistant
        transform: "value / 6000" # Optional: a transform function written in JavaScript
        template: "{{ value | float(0) / 6000 }}" # Optional: a HA template to get the state of the sensor (Used for Discovery).
        icon: mdi:calendar-clock # Optional: set an icon in Home Assistant
        device_class: temperature # Optional: set the Home Assistant class of the device.
        entity_category: diagnostic # Optional: set the Home Assistant entity category.
        binary_sensor: false # Optional: whether to expose the sensor as a binary sensor in Home Assistant
        availability_mode: any # Optional: Valid entries are all, any, latest and online. (default: all)

  - host: 192.168.0.3
    name: Raspberry Pi 2
    version: 2c
    sensors:
      - oid: 1.3.6.1.2.1.25.1.1.0
        name: Raspberry Pi 2 Uptime
        unit_of_measurement: days
        transform: "Math.floor(value / 6000 / 60 / 24)"
        icon: mdi:calendar-clock

      - oid: 1.3.6.1.4.1.2021.11.11.0
        name: Raspberry Pi 2 CPU
        unit_of_measurement: "%"
        transform: "100 - value"
        icon: mdi:cpu-64-bit