> 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/continuous-delivery/3.0/use-deployments/kubernetes/step-library/k8s-rolling-deploy.md).

# Kubernetes Rolling Deploy

The Kubernetes Rolling Deploy step prepares your manifests, applies them to the cluster using `kubectl apply`, and waits for all pods to reach steady state. Kubernetes replaces pods incrementally using its native `RollingUpdate` strategy. Use this step in a rolling stage, or as the promotion step at the end of a canary stage.

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### Before you begin <a href="#before-you-begin" id="before-you-begin"></a>

Before you configure the step, make sure you have the following in place:

* **A Kubernetes service:** Go [Kubernetes services](/continuous-delivery/3.0/use-deployments/kubernetes/kubernetes-services.md) to set up your service manifests and artifact source.
* **A Kubernetes infrastructure:** Go [Kubernetes infrastructure](/continuous-delivery/3.0/use-deployments/kubernetes/kubernetes-infrastructure.md) to connect your cluster and namespace.
* **A Harness delegate in the target cluster:** The delegate runs deployment steps in the cluster.
* **Runtime configuration:** Every Kubernetes stage requires a `runtime` block specifying the connector and namespace. Go [Kubernetes runtime configuration](/continuous-delivery/3.0/use-deployments/kubernetes/overview.md#kubernetes-runtime-configuration) to understand the required fields.

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### Configure the step <a href="#configure-the-step" id="configure-the-step"></a>

The following parameters are available on the Kubernetes Rolling Deploy step.

| Parameter              | Description                                                                                                                                               | Required |
| ---------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- |
| **Name**               | Display name for this step in the stage canvas. Default: `Kubernetes Rolling Deploy`.                                                                     | Required |
| **Skip Dry Run**       | When enabled, skips the `kubectl apply --dry-run` pre-validation before the actual apply. Default: `false`.                                               | Optional |
| **Kubernetes Pruning** | When enabled, Harness removes resources from the cluster that exist in the previous release but are no longer in the current manifests. Default: `false`. | Optional |
| **Manifest Path**      | Override the manifest paths from the service configuration. Leave empty to use all manifests from the service.                                            | Optional |
| **Kubeconfig Path**    | Path to the kubeconfig file. Default: `${{infra.kube_config_path}}`.                                                                                      | Optional |
| **Namespace**          | Target namespace for the deployment. Default: `${{infra.namespace}}`.                                                                                     | Optional |
| **Release Name**       | Name used to track Harness release history in the cluster. Default: `${{infra.releaseName}}`.                                                             | Optional |
| **Log Level**          | Verbosity of step logs. Default: `info`.                                                                                                                  | Optional |

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

When the step runs, it performs three internal actions:

1. **Kubernetes Rolling Prepare Action:** Reads your manifests, increments the release number, versions ConfigMaps and Secrets, labels all pods with `harness.io/track=stable`, and writes the prepared manifests to the workspace. Harness saves the release state as a Kubernetes Secret in the target namespace.
2. **Kubernetes Apply Action:** Applies the prepared manifests to your cluster using `kubectl apply`. Kubernetes performs the rolling update natively, incrementally replacing old pods with new pods according to the `maxSurge` and `maxUnavailable` settings in your Deployment manifest.
3. **Kubernetes Steady State Check Action:** Polls the cluster until all pods in the Deployment reach `Running` status and pass readiness checks, or until the step timeout is reached.

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### Advanced settings <a href="#advanced-settings" id="advanced-settings"></a>

* **Timeout duration:** Maximum time the step is allowed to run before being terminated.
* **On failure:** Define what happens if the step fails, such as retry, mark as success, or abort.
* **Strategy:** Configure a looping strategy to run this step over a list of values.
* **Conditional execution:** Run this step only when a specified condition is true.

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### Next steps <a href="#next-steps" id="next-steps"></a>

* Go [Kubernetes rolling deployment](/continuous-delivery/3.0/use-deployments/kubernetes/kubernetes-deployment-strategies/rolling.md) to understand the full rolling deployment flow.
* Go [Kubernetes Rolling Rollback](/continuous-delivery/3.0/use-deployments/kubernetes/step-library/k8s-rolling-rollback.md) to configure the rollback step for this strategy.