> 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-engineering/faults/chaos-fault-categories/kubernetes/node/common-tunables-for-node-faults.md).

# Common node fault tunables

These tunables apply to every node-level chaos fault in Harness Chaos Engineering. Set them on the fault in Chaos Studio to choose which nodes the experiment targets.

***

### Target single node <a href="#target-single-node" id="target-single-node"></a>

Use the `TARGET_NODE` environment variable to name the single node the fault should run against.

| Tunable       | Description                 | Default |
| ------------- | --------------------------- | ------- |
| `TARGET_NODE` | Name of the node to target. | `""`    |

Supported by: [Node drain](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-drain.md), [Node taint](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-taint.md), [Node restart](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-restart.md), [Kubelet service kill](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/kubelet-service-kill.md).

```yaml
- name: TARGET_NODE
  value: "node01"
```

***

### Target multiple nodes <a href="#target-multiple-nodes" id="target-multiple-nodes"></a>

Use the `TARGET_NODES` environment variable to target a comma-separated list of nodes.

| Tunable        | Description                                   | Default |
| -------------- | --------------------------------------------- | ------- |
| `TARGET_NODES` | Comma-separated list of node names to target. | `""`    |

Supported by: [Node CPU hog](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-cpu-hog.md), [Node memory hog](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-memory-hog.md), [Node I/O stress](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-io-stress.md), [Node network loss](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-network-loss.md), [Node network latency](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-network-latency.md).

```yaml
- name: TARGET_NODES
  value: "node01,node02"
```

***

### Target nodes with labels <a href="#target-nodes-with-labels" id="target-nodes-with-labels"></a>

Use the `NODE_LABEL` environment variable to select target nodes by label. This is mutually exclusive with `TARGET_NODE` and `TARGET_NODES`. If both are set, the explicit node list wins.

| Tunable      | Description                                                                     | Default |
| ------------ | ------------------------------------------------------------------------------- | ------- |
| `NODE_LABEL` | Label selector in `key=value` form. The fault targets nodes whose labels match. | `""`    |

```yaml
- name: NODE_LABEL
  value: "kubernetes.io/role=worker"
```

***

### Node affected percentage <a href="#node-affected-percentage" id="node-affected-percentage"></a>

Use the `NODES_AFFECTED_PERCENTAGE` environment variable to target a percentage of nodes that match the label selector. A value of `0` (the default) means one node.

| Tunable                     | Description                                                                | Default |
| --------------------------- | -------------------------------------------------------------------------- | ------- |
| `NODES_AFFECTED_PERCENTAGE` | Percentage of nodes (matching the selector) to target. `0` means one node. | `0`     |

Supported by: [Node CPU hog](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-cpu-hog.md), [Node memory hog](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-memory-hog.md), [Node I/O stress](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/node-io-stress.md).

```yaml
- name: NODES_AFFECTED_PERCENTAGE
  value: "100"
- name: NODE_LABEL
  value: "kubernetes.io/role=worker"
```