> 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

Prepare manifests, apply them to the cluster, and wait for all pods to reach steady state.

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.

{% @harness-feedback/feedback %}