> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vms.verolabs.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Probe: container_mon

> Monitor Docker / Docker Swarm containers

<Warning>
  This probe is on the development roadmap.
</Warning>

## Description

The `container_mon` probe monitors Docker and Docker Swarm containers via the Docker Engine API (HTTP over unix socket). Tracks running state, restart count, and optional CPU/memory stats.

Build tag `vms_heavy`.

## Config fields

| Field                  | Type     | Required | Default                | Description                                    |
| ---------------------- | -------- | -------- | ---------------------- | ---------------------------------------------- |
| `type`                 | `string` | Yes      | —                      | Must be `"container_mon"`                      |
| `runtime`              | `string` | Yes      | —                      | `"docker"` or `"docker_swarm"`                 |
| `runtimeEndpoint`      | `string` | No       | `/var/run/docker.sock` | Docker socket path                             |
| `containerNamePattern` | `string` | No       | —                      | Regex to match container names. Empty = all    |
| `serviceName`          | `string` | No       | —                      | Docker Swarm service name                      |
| `collectStats`         | `bool`   | No       | `false`                | Collect CPU% and memory for running containers |

## Metrics

| Metric                             | Type    | Unit    | Labels      | Description         |
| ---------------------------------- | ------- | ------- | ----------- | ------------------- |
| `vms.container_mon.status`         | status  | —       | `container` | Per-container state |
| `vms.container_mon.restart_count`  | counter | —       | `container` | Restart count       |
| `vms.container_mon.cpu_percent`    | gauge   | percent | `container` | CPU usage           |
| `vms.container_mon.memory_bytes`   | gauge   | bytes   | `container` | Memory usage        |
| `vms.container_mon.memory_percent` | gauge   | percent | `container` | Memory usage %      |

## Example config

```json theme={null}
{
  "type": "container_mon",
  "runtime": "docker",
  "containerNamePattern": "core-.*",
  "collectStats": true
}
```

## Notes

* Max **50 containers** matched per run.
* Docker socket unreachable → status `unknown`, emits `vms.agent.permission_missing{capability=docker.sock}`.
* Build tag `vms_heavy` — not in default agent package.