---
title: Set agent statuses
description: Configure agent status evaluation using CEL expressions in the Telegraf heartbeat output plugin and view statuses in Telegraf Controller.
url: https://docs.influxdata.com/telegraf/controller/agents/status/
estimated_tokens: 3844
product: Telegraf
version: v1
---

# Set agent statuses

#### Telegraf Controller is in Public Beta

Telegraf Controller is in public beta and will be part of the future Telegraf Enterprise offering. While in beta, Telegraf Controller is **not meant for production use**. The Telegraf Controller documentation is a work in progress, and we are actively working to improve it. If you have any questions or suggestions, please [submit an issue](https://github.com/influxdata/docs-v2/issues/new?labels=Telegraf%20Controller). We welcome any and all contributions.

Beta expectations

-   **No configuration or agent limits**  
    While in beta, Telegraf Controller doesn't place any limits on the number of configurations you can store or the number of Telegraf agents you can track. However, upon being generally available, the free distribution of Telegraf Controller will have limits introduced, with the option to increase limits through a Telegraf Enterprise license.
-   **Potential breaking changes**  
    While in beta, we will do our best to no longer make breaking changes to Telegraf Controller, however, they may be necessary. The majority of changes we make will be additive and non-breaking, and include any necessary migrations. When we do need to make breaking changes, we will do our best to communicate them clearly and in advance to minimize disruption.
-   **Flexible release schedule**  
    While in beta, we will continue to create new releases of Telegraf Controller, but likely at irregular intervals. We will provide [Telegraf Controller release notes](/telegraf/controller/reference/release-notes/) to make it easy to track updates.

Provide beta feedback

-   Use the **Feedback** feature in the Telegraf Controller UI.
-   [Join the InfluxDB Community Slack](https://influxdata.com/slack) and post feedback in the **#telegraf-enterprise-alpha** channel.
-   Post feedback in the [InfluxData Community](https://community.influxdata.com).

Join our public channels

-   [InfluxDB Community Slack *(Preferred)*](https://influxdata.com/slack)
-   [InfluxData Community](https://community.influxdata.com)
-   [InfluxDB Subreddit](https://reddit.com/r/influxdb)

Agent statuses reflect the health of a Telegraf instance based on runtime data. The Telegraf [heartbeat output plugin](/telegraf/v1/output-plugins/heartbeat/) evaluates [Common Expression Language (CEL)](/telegraf/controller/reference/agent-status-eval/) expressions against agent metrics, error counts, and plugin statistics to determine the status sent with each heartbeat.

#### Requires Telegraf v1.38.2+

Agent status evaluation in the Heartbeat output plugins requires Telegraf v1.38.2+.

## Status values

Telegraf Controller displays the following agent statuses:

| Status | Source | Description |
| --- | --- | --- |
| Ok | Heartbeat plugin | The agent is healthy. Set when the ok CEL expression evaluates to true. |
| Warn | Heartbeat plugin | The agent has a potential issue. Set when the warn CEL expression evaluates to true. |
| Fail | Heartbeat plugin | The agent has a critical problem. Set when the fail CEL expression evaluates to true. |
| Undefined | Heartbeat plugin | No expression matched and the default is set to undefined, or the initial status is undefined. |
| Not Reporting | Telegraf Controller | The agent has not sent a heartbeat within the reporting rule threshold. Telegraf Controller applies this status automatically. |

## How status evaluation works

You define CEL expressions for `ok`, `warn`, and `fail` in the `[outputs.heartbeat.status]` section of your heartbeat plugin configuration. Telegraf evaluates expressions in a configurable order and assigns the status of the first expression that evaluates to `true`.

For full details on evaluation flow, configuration options, and available variables and functions, see the [Agent status evaluation reference](/telegraf/controller/reference/agent-status-eval/).

## Configure agent statuses

To configure status evaluation, add `"status"` to the `include` list in your heartbeat plugin configuration and define CEL expressions in the `[outputs.heartbeat.status]` section.

### Example: Basic health check

Report `ok` when metrics are flowing. If no metrics arrive, fall back to the `fail` status.

```toml
[[outputs.heartbeat]]
  url = "http://telegraf_controller.example.com/agents/heartbeat"
  instance_id = "&{agent_id}"
  token = "${INFLUX_TOKEN}"
  interval = "1m"
  include = ["hostname", "statistics", "configs", "logs", "status"]

  [outputs.heartbeat.status]
    ok = "metrics > 0"
    default = "fail"
```

### Example: Error-based status

Warn when errors are logged, fail when the error count is high.

```toml
[[outputs.heartbeat]]
  url = "http://telegraf_controller.example.com/agents/heartbeat"
  instance_id = "&{agent_id}"
  token = "${INFLUX_TOKEN}"
  interval = "1m"
  include = ["hostname", "statistics", "configs", "logs", "status"]

  [outputs.heartbeat.status]
    ok = "log_errors == 0 && log_warnings == 0"
    warn = "log_errors > 0"
    fail = "log_errors > 10"
    order = ["fail", "warn", "ok"]
    default = "ok"
```

### Example: Composite condition

Combine error count and buffer pressure signals.

```toml
[[outputs.heartbeat]]
  url = "http://telegraf_controller.example.com/agents/heartbeat"
  instance_id = "&{agent_id}"
  token = "${INFLUX_TOKEN}"
  interval = "1m"
  include = ["hostname", "statistics", "configs", "logs", "status"]

  [outputs.heartbeat.status]
    ok = "metrics > 0 && log_errors == 0"
    warn = "log_errors > 0 || (has(outputs.influxdb_v2) && outputs.influxdb_v2.exists(o, o.buffer_fullness > 0.8))"
    fail = "log_errors > 5 && has(outputs.influxdb_v2) && outputs.influxdb_v2.exists(o, o.buffer_fullness > 0.9)"
    order = ["fail", "warn", "ok"]
    default = "ok"
```

For more examples including buffer health, plugin-specific checks, and time-based expressions, see [CEL expression examples](/telegraf/controller/reference/agent-status-eval/examples/).

## View an agent’s status

1. In Telegraf Controller, go to **Agents**.
2. Check the **Status** column for each agent.
3. To see more details, click the **More button (⋮)** and select **View Details**.
4. The details page shows the reported status, reporting rule assignment, and the time of the last heartbeat.

#### Related

-   [Agent status evaluation reference](/telegraf/controller/reference/agent-status-eval/)
-   [Define agent reporting rules](/telegraf/controller/agents/reporting-rules/)
-   [Heartbeat output plugin](/telegraf/v1/output-plugins/heartbeat/)