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Description

The connection_mon probe checks whether a specific process currently holds an ESTABLISHED TCP connection to a service endpoint. Designed for “trace between two servers” — verifying connectivity between systems. Bidirectional matching: The same config can be deployed on both ends:
  • Forward: this host is the source (local = source, remote = dest service)
  • Reverse: this host is the dest (local = dest service, remote = source)
Requires both ProcessAdapter and ConnAdapter.

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Config fields

FieldTypeRequiredDefaultDescription
typestringYes—Must be "connection_mon"
namestringYes—Connection link identifier
processNamestringYes—Process name glob (case-insensitive, same as process_mon)
executablePathstringNo—Executable path to narrow match (ANDed)
destServiceIpstringYes—Destination service IP (well-known end)
destServicePortintYes—Destination service port (1–65535)
sourceServiceIpstringNo—Source IP (optional filter)
sourceServicePortintNo—Source port (usually ephemeral, left unset)
protocolstringNo"tcp"Only "tcp" supported

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Metrics

MetricTypeLabelsDescription
vms.connection_mon.statusstatusname, dest_ip, dest_port, proto, process_name, directionup or down
vms.connection_mon.upgauge(same)1 = ESTABLISHED connection found, 0 = none
vms.agent.permission_missinggaugecapability=CAP_SYS_PTRACEWhen agent cannot attribute sockets to PIDs

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Example config

{
  "type": "connection_mon",
  "name": "app-to-postgres",
  "processName": "java",
  "destServiceIp": "10.0.1.50",
  "destServicePort": 5432
}

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Notes

  • Only TCP ESTABLISHED state is considered “normal/healthy”.
  • Same config deployed on both ends: host A sees direction=forward, host B sees direction=reverse.
  • Without CAP_SYS_PTRACE, a process owned by another user shows 0 connections (false negative) with vms.agent.permission_missing emitted.