doc: add document for fleet

Signed-off-by: Yang Chiu <yang.chiu@suse.com>

content/docs/1.6.0/deploy/install/_index.md

@@ -12,6 +12,7 @@ Longhorn can be installed on a Kubernetes cluster in several ways:
 - [Rancher catalog app](./install-with-rancher)
 - [kubectl](./install-with-kubectl/)
 - [Helm](./install-with-helm/)
+- [Fleet](./install-with-fleet/)
 
 To install Longhorn in an air gapped environment, refer to [this section.](../../advanced-resources/deploy/airgap)
 

content/docs/1.6.0/deploy/install/install-with-fleet.md

@@ -0,0 +1,152 @@
+---
+title: Install with Fleet
+weight: 10
+---
+
+## Prerequisites
+- Your workstation: Install [Helm](https://helm.sh/docs/) v3.0 or later.
+- Kubernetes cluster:
+  - Ensure that each node fulfills the [installation requirements](../#installation-requirements).
+  - Install [Fleet](https://fleet.rancher.io/) using Helm.
+
+    ```bash
+    helm repo add fleet https://rancher.github.io/fleet-helm-charts/
+    helm -n cattle-fleet-system install --create-namespace --wait fleet-crd fleet/fleet-crd
+    helm -n cattle-fleet-system install --create-namespace --wait fleet fleet/fleet
+    ```
+    Allow some time for the deployment of Fleet components in the `cattle-fleet-system` namespace.
+
+> Use [this script](https://github.com/longhorn/longhorn/blob/v{{< current-version >}}/scripts/environment_check.sh) to check the Longhorn environment for potential issues.
+
+## Installing Longhorn
+
+1. In your GitOps repository, create a [fleet.yaml](https://fleet.rancher.io/ref-fleet-yaml) file that includes the following:
+
+    - Parameter for installing Longhorn in the `longhorn-system` namespace
+
+    ```yaml
+    defaultNamespace: longhorn-system
+    ```
+
+    - Parameters for [ignoring modified CRDs](https://fleet.rancher.io/bundle-diffs)
+
+    ```yaml
+    diff:
+      comparePatches:
+      - apiVersion: apiextensions.k8s.io/v1
+        kind: CustomResourceDefinition
+        name: engineimages.longhorn.io
+        operations:
+        - {"op": "replace", "path": "/status"}
+      - apiVersion: apiextensions.k8s.io/v1
+        kind: CustomResourceDefinition
+        name: nodes.longhorn.io
+        operations:
+        - {"op": "replace", "path": "/status"}
+      - apiVersion: apiextensions.k8s.io/v1
+        kind: CustomResourceDefinition
+        name: volumes.longhorn.io
+        operations:
+        - {"op": "replace", "path": "/status"}
+    ```
+
+    - Parameters for specifying the version of the Longhorn Helm chart to be installed
+
+    ```yaml
+    helm:
+      repo: https://charts.longhorn.io
+      chart: longhorn
+      version: v1.6.0 # Replace with the Longhorn version you'd like to install or upgrade to
+      releaseName: longhorn
+    ```
+
+    Example of a complete `fleet.yaml` file:
+
+    ```yaml
+    defaultNamespace: longhorn-system
+    helm:
+      repo: https://charts.longhorn.io
+      chart: longhorn
+      version: 1.6.0
+      releaseName: longhorn
+    diff:
+      comparePatches:
+      - apiVersion: apiextensions.k8s.io/v1
+        kind: CustomResourceDefinition
+        name: engineimages.longhorn.io
+        operations:
+        - {"op": "replace", "path": "/status"}
+      - apiVersion: apiextensions.k8s.io/v1
+        kind: CustomResourceDefinition
+        name: nodes.longhorn.io
+        operations:
+        - {"op": "replace", "path": "/status"}
+      - apiVersion: apiextensions.k8s.io/v1
+        kind: CustomResourceDefinition
+        name: volumes.longhorn.io
+        operations:
+        - {"op": "replace", "path": "/status"}
+    ```
+
+1. Create a GitRepo custom resource (CR) that points to your GitOps repository.
+
+    ```bash
+    cat > longhorn-gitrepo.yaml << "EOF"
+    apiVersion: fleet.cattle.io/v1alpha1
+    kind: GitRepo
+    metadata:
+      name: longhorn
+      namespace: fleet-local
+    spec:
+      repo: https://github.com/your-username/your-gitops-repo.git
+      revision: main
+      paths:
+      - .
+    EOF
+    ```
+
+1. Apply the GitRepo CR.
+
+    ```bash
+    kubectl apply -f longhorn-gitrepo.yaml
+    ```
+
+1. Verify that the GitRepo CR was created and synced successfully.
+
+    ```bash
+    kubectl -n fleet-local get fleet -w
+    ```
+
+1. Verify that Longhorn was installed successfully.
+
+    ```bash
+    kubectl -n longhorn-system get pod
+    ```
+
+    Example of a successful Longhorn installation:
+
+    ```bash
+    NAME                                                READY   STATUS    RESTARTS   AGE
+    longhorn-ui-b7c844b49-w25g5                         1/1     Running   0          2m41s
+    longhorn-manager-pzgsp                              1/1     Running   0          2m41s
+    longhorn-driver-deployer-6bd59c9f76-lqczw           1/1     Running   0          2m41s
+    longhorn-csi-plugin-mbwqz                           2/2     Running   0          100s
+    csi-snapshotter-588457fcdf-22bqp                    1/1     Running   0          100s
+    csi-snapshotter-588457fcdf-2wd6g                    1/1     Running   0          100s
+    csi-provisioner-869bdc4b79-mzrwf                    1/1     Running   0          101s
+    csi-provisioner-869bdc4b79-klgfm                    1/1     Running   0          101s
+    csi-resizer-6d8cf5f99f-fd2ck                        1/1     Running   0          101s
+    csi-provisioner-869bdc4b79-j46rx                    1/1     Running   0          101s
+    csi-snapshotter-588457fcdf-bvjdt                    1/1     Running   0          100s
+    csi-resizer-6d8cf5f99f-68cw7                        1/1     Running   0          101s
+    csi-attacher-7bf4b7f996-df8v6                       1/1     Running   0          101s
+    csi-attacher-7bf4b7f996-g9cwc                       1/1     Running   0          101s
+    csi-attacher-7bf4b7f996-8l9sw                       1/1     Running   0          101s
+    csi-resizer-6d8cf5f99f-smdjw                        1/1     Running   0          101s
+    instance-manager-b34d5db1fe1e2d52bcfb308be3166cfc   1/1     Running   0          114s
+    engine-image-ei-df38d2e5-cv6nc                      1/1     Running   0          114s
+    ```
+
+1. [Create an NGINX Ingress controller with basic authentication](../../accessing-the-ui/longhorn-ingress) to access the Longhorn UI. Authentication to the Longhorn UI is not enabled by default.
+
+1. [Access the Longhorn UI](../../accessing-the-ui).