> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/resilience-testing/chaos-testing/probes/probe-template-library/kubernetes/node-status-check.md).

# Node Status Check

Node Status Check is a built-in Command Probe template that validates the current state of Kubernetes nodes during a chaos experiment. It confirms that the targeted nodes stay healthy and `Ready`, so you can assert that cluster capacity holds up while a node-level fault is injected. You select nodes by name or by label.

The probe runs the `healthchecks` utility bundled in the chaos probe image, queries the Kubernetes API, and prints `[Pass]` when every targeted node is healthy. The comparator marks the probe as passed when the output contains `[Pass]`.

{% hint style="info" %}
**BUILT-IN PROBE TEMPLATE**

This is a built-in Command Probe template that runs on Kubernetes chaos infrastructure. Add it to an experiment from the probe library and customize its inputs. Go to [Built-in probe templates](/resilience-testing/chaos-testing/probes/probe-templates.md) to browse the full library, or go to [Command probe](/resilience-testing/chaos-testing/probes/command-probe.md) to understand how command probes work.
{% endhint %}

***

### Use cases <a href="#use-cases" id="use-cases"></a>

Use this probe template to:

* Verify that nodes stay healthy during chaos experiments.
* Validate node recovery after failures.
* Monitor cluster health during node-level chaos.
* Confirm node availability during infrastructure disruptions.

***

### How the probe works <a href="#how-the-probe-works" id="how-the-probe-works"></a>

The template configures a Command Probe that runs `healthchecks -name node-level`. The utility resolves the target nodes from `TARGET_NODE`, `TARGET_NODES`, or `NODE_LABEL`, queries the Kubernetes API, and prints `[Pass]` when every resolved node is in a healthy state. The comparator passes the probe when the output contains `[Pass]`, and fails it otherwise.

***

### Prerequisites <a href="#prerequisites" id="prerequisites"></a>

* **Chaos infrastructure:** A Kubernetes chaos infrastructure installed in the target cluster.
* **Node access:** Access to the cluster nodes you want to check.
* **RBAC permissions:** Permissions for the chaos service account to query node status.

***

### Probe properties <a href="#probe-properties" id="probe-properties"></a>

#### Command <a href="#command" id="command"></a>

```bash
healthchecks -name node-level
```

#### Comparator <a href="#comparator" id="comparator"></a>

| Type   | Criteria | Value    |
| ------ | -------- | -------- |
| string | contains | `[Pass]` |

The probe passes when the command output contains `[Pass]`, which indicates that every targeted node is in a healthy state.

#### Environment variables <a href="#environment-variables" id="environment-variables"></a>

| Variable               | Description                                                                                                                                             | Required    | Default |
| ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------- | ------- |
| `TARGET_NODE`          | Comma-separated list of nodes to check. Provide one of `TARGET_NODE`, `TARGET_NODES`, or `NODE_LABEL`.                                                  | Conditional | -       |
| `TARGET_NODES`         | Comma-separated list of nodes to check. Provide one of `TARGET_NODE`, `TARGET_NODES`, or `NODE_LABEL`.                                                  | Conditional | -       |
| `NODE_LABEL`           | Node label used to list nodes to check (for example, `node-role.kubernetes.io/worker=`). Provide one of `TARGET_NODE`, `TARGET_NODES`, or `NODE_LABEL`. | Conditional | -       |
| `STATUS_CHECK_TIMEOUT` | Maximum time in seconds to wait for the status check.                                                                                                   | No          | `180`   |
| `STATUS_CHECK_DELAY`   | Delay in seconds between status checks.                                                                                                                 | No          | `2`     |

{% hint style="info" %}
**NODE SELECTION**

Provide at least one of `TARGET_NODE`, `TARGET_NODES`, or `NODE_LABEL`.
{% endhint %}

***

### Run properties <a href="#run-properties" id="run-properties"></a>

| Property          | Description                                                                      | Type    | Default |
| ----------------- | -------------------------------------------------------------------------------- | ------- | ------- |
| `timeout`         | Maximum time to wait for the probe to complete (for example, `30s`, `1m`, `5m`). | String  | `180s`  |
| `interval`        | Time between probe executions (for example, `1s`, `5s`, `10s`).                  | String  | `1s`    |
| `attempt`         | Number of retry attempts before the probe is marked as failed.                   | Integer | `1`     |
| `pollingInterval` | Time between retry attempts (for example, `1s`, `5s`, `10s`).                    | String  | -       |
| `initialDelay`    | Initial delay before the probe starts (for example, `0s`, `10s`, `30s`).         | String  | -       |
| `stopOnFailure`   | Stop the experiment if the probe fails.                                          | Boolean | `false` |
| `verbosity`       | Log verbosity level (`info`, `debug`, `trace`).                                  | String  | -       |

***

### Troubleshooting <a href="#troubleshooting" id="troubleshooting"></a>

<details>

<summary>Node Status Check probe fails because no nodes matched the target</summary>

The selectors did not resolve any nodes. Confirm that the values in TARGET\_NODE or TARGET\_NODES match node names exactly, or that NODE\_LABEL matches a label applied to the nodes. An empty match is treated as a failure.

</details>

<details>

<summary>Node Status Check probe fails with a forbidden or RBAC error</summary>

The chaos service account does not have permission to read nodes. Nodes are cluster-scoped, so grant get and list on nodes through a ClusterRole and ClusterRoleBinding for the chaos service account, then rerun the experiment.

</details>

<details>

<summary>Node Status Check probe times out before the node becomes Ready</summary>

The node did not return to a Ready state within STATUS\_CHECK\_TIMEOUT. Increase STATUS\_CHECK\_TIMEOUT and the run-property timeout, and inspect the node with kubectl describe node to find NotReady conditions, taints, or kubelet issues.

</details>

***

### Related probe templates <a href="#related-probe-templates" id="related-probe-templates"></a>

* [Pod Status Check](/resilience-testing/chaos-testing/probes/probe-template-library/kubernetes/pod-status-check.md): Validate that pods stay in the Running state.
* [Pod Replica Count Check](/resilience-testing/chaos-testing/probes/probe-template-library/kubernetes/pod-replica-count-check.md): Validate that a workload keeps its minimum healthy replicas.
* [Built-in probe templates](/resilience-testing/chaos-testing/probes/probe-templates.md): Browse the full probe template library.