net.hostname: React to Hostname Changes

The net.hostname sensor watches the local system hostname and emits an event whenever the hostname changes.

This sensor is backed by omnitrace/nettools and is intentionally narrow: it only watches hostname transitions and keeps a stable JSON payload for event handlers.

Synopsis

Sensor configuration as follows:

<id>:
    [profile]:
      - <id>

    description: <description>
    listener: net.hostname
    tag: <event name> # optional, default is net.hostname
    interval: <duration> # optional, default 3s

    args:
        locked: true|false # optional, default false (emit once until handler unlocks)

profile

Optional

The list of profiles to which this sensor belongs. If current Minion is attached to any other profile, the sensor will be inactive.

description

A human-readable description of the sensor.

listener

The type of listener used by the sensor. In this case, it is net.hostname.

interval

Poll interval for hostname checks. If omitted, the sensor uses a conservative default of 3s.

args

Arguments specific to net.hostname:

• locked (optional): if true, the same event is sent only once and then muted. It will be sent again only after your event handler explicitly releases/unlocks it.

tag

An optional tag to associate with the event. If specified, the event name will include this tag, allowing easier identification and filtering of events.

Event ID format:

<sensor-id>|net.hostname[@tag]|changed@<new-hostname>|0

Payload

The emitted JSON envelope contains the usual libsensors metadata and a small hostname-specific payload:

{
  "eid": "host-watch|net.hostname|changed@new-name|0",
  "sensor": "host-watch",
  "listener": "net.hostname",
  "data": {
    "action": "changed",
    "old": "old-name",
    "new": "new-name"
  }
}

Example

Here is an example of how to watch hostname changes:

host-watch:
    description: Watch hostname changes
    listener: net.hostname
    interval: 2s
    args:
        locked: false
    tag: host

Demo

See the demo material under:

examples/demos/net/