Vero Monitor Service

Description

The check_port probe performs a TCP connect to verify whether a port on a host is reachable. Supports both expecting the port to be open (default) and expecting it to be closed. This is an active check — emits both metrics and a check result with latency.

Config fields

Field	Type	Required	Default	Description
`type`	`string`	Yes	—	Must be `"check_port"`
`host`	`string`	Yes	—	Host or IP to check
`port`	`int`	Yes	—	TCP port (1–65535)
`expectOpen`	`bool`	No	`true`	`true`: expect port open → `up` on successful connect. `false`: expect port closed → `up` on connect failure

Metrics

Metric	Type	Unit	Description
`vms.check_port.status`	status	—	`up` or `down`
`vms.check_port.latency_ms`	gauge	ms	TCP connect time

Example config

{
  "type": "check_port",
  "host": "10.0.0.10",
  "port": 443,
  "expectOpen": true
}

Check that a port is closed:

{
  "type": "check_port",
  "host": "10.0.0.10",
  "port": 3389,
  "expectOpen": false
}

Notes

When the result doesn’t match the expectation, severity is critical.
A connect failure due to network is a normal result (status=down), not an agent error.