Managing Helm releases guide

docs/guides/helmreleases.md

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+# Managing Helm releases
+
+The [helm-controller](../components/helm/controller.md) allows you to
+declaratively manage Helm chart releases with Kubernetes manifests.
+It makes use of the artifacts produced by the
+[source-controller](../components/source/controller.md) from
+`HelmRepository` and `HelmChart` resources.
+The helm-controller is part of the default toolkit installation.
+
+## Prerequisites
+
+To follow this guide you'll need a Kubernetes cluster with the GitOps 
+toolkit controllers installed on it.
+Please see the [get started guide](../get-started/index.md)
+or the [install command docs](../cmd/tk_install.md).
+
+## Define a Helm repository
+
+To be able to deploy a Helm chart, the Helm chart repository has to be
+known first to the source-controller, so that the `HelmRelease` can
+reference to it.
+
+A cluster administrator should register trusted sources by creating
+`HelmRepository` resources in the `gitops-system` namespace.
+By default, the source-controller watches for sources only in the
+`gitops-system` namespace, this way cluster admins can prevent
+untrusted sources from being registered by users.
+
+```yaml
+apiVersion: source.fluxcd.io/v1alpha1
+kind: HelmRepository
+metadata:
+  name: podinfo
+  namespace: gitops-system
+spec:
+  interval: 1m
+  url: https://stefanprodan.github.io/podinfo
+```
+
+The `interval` defines at which interval the Helm repository index
+is fetched, and should be at least `1m`. Setting this to a higher
+value means newer chart versions will be detected at a slower pace,
+a push-based fetch can be introduced using [webhook receivers](webhook-receivers.md)
+
+The `url` can be any HTTP/S Helm repository URL.
+
+!!! hint "Authentication"
+    HTTP/S basic and TLS authentication can be configured for private
+    Helm repositories. See the [`HelmRepository` CRD docs](../components/source/helmrepositories.md)
+    for more details.
+
+## Define a Helm release
+
+With the `HelmRepository` created, define a new `HelmRelease` to deploy
+the Helm chart from the repository:
+
+```yaml
+apiVersion: helm.fluxcd.io/v2alpha1
+kind: HelmRelease
+metadata:
+  name: podinfo
+  namespace: default
+spec:
+  interval: 5m
+  chart:
+    name: podinfo
+    version: '^4.0.0'
+    sourceRef:
+      kind: HelmRepository
+      name: podinfo
+      namespace: gitops-system
+    interval: 1m
+  values:
+    replicaCount: 2
+```
+
+The `chart.name` is the name of the chart as made available by the Helm
+repository, and may not include any aliases.
+
+The `chart.version` can be a fixed semver, or any semver range (i.e.
+`>=4.0.0 <4.0.2`).
+
+The `chart` values are used by the helm-controller as a template to
+create a new `HelmChart` resource in the same namespace as the
+`sourceRef`. The source-controller will then lookup the chart in the
+artifact of the referenced `HelmRepository`, fetch the chart, and make
+it available as a `HelmChart` artifact to be used by the
+helm-controller.
+
+!!! Note
+    The `HelmRelease` offers an extensive set of configurable flags
+    for finer grain control over how Helm actions are performed.
+    See the [`HelmRelease` CRD docs](../components/helm/helmreleases.md)
+    for more details.