Description
The tls_cert probe connects to a host via TLS, reads the leaf certificate, and calculates days remaining before expiry. Supports warning and critical thresholds.
Certificate verification is intentionally disabled — the probe reads expired or self-signed certificates to report accurate days remaining.
Config fields
| Field | Type | Required | Default | Description |
|---|
type | string | Yes | — | Must be "tls_cert" |
host | string | Yes | — | Host for TLS connection and SNI |
port | int | Yes | — | TLS port (1–65535) |
warningDays | int | No | 0 | Days remaining threshold for warning. 0 = no warning |
criticalDays | int | No | 0 | Days remaining threshold for critical. 0 = no critical alert |
If both warningDays and criticalDays are > 0, criticalDays must be ≤ warningDays.
Metrics
| Metric | Type | Unit | Description |
|---|
vms.tls_cert.days_remaining | gauge | days | Days until cert expiry. -1 if TLS handshake failed |
Example config
{
"type": "tls_cert",
"host": "app.verolabs.co",
"port": 443,
"warningDays": 30,
"criticalDays": 7
}
