Add the Flux integration use case (#235)

Co-authored-by: egrosdou <egrosdou@cisco.com>

docs/use_cases/use_case_flux_integration.md

@@ -0,0 +1,86 @@
+---
+title: Sveltos - Kubernetes Add-on Controller | Manage Kubernetes Add-ons with Ease
+description: Sveltos is an application designed to manage hundreds of clusters by providing declarative APIs to deploy Kubernetes add-ons across multiple clusters.
+tags:
+ - Kubernetes
+ - add-ons
+ - helm
+ - kustomize
+ - clusterapi
+ - multi-tenancy
+ - Sveltos
+authors:
+ - Eleni Grosdouli
+---
+
+## Introduction to Sveltos and Flux
+
+With the latest release of Sveltos [v0.23.0](https://github.com/orgs/projectsveltos/discussions/454), the existing integration with [Flux](https://fluxcd.io/) is greatly enhanced. Flux is a CNCF graduate project that offers users a set of continuous and progressive delivery solutions for Kubernetes which are open and extensible.
+
+By integrating Flux with Sveltos, we can automate the synchronisation of the desired Kubernetes add-ons, removing any manual steps and ensuring consistent deployment across clusters.
+
+![Flux and Sveltos Integration](../assets/flux_and_sveltos.png)
+
+## What are the benefits of the integration?
+
+1. **Centralised Configuration:** Store YAML/JSON manifests in a central Git repository or a bucket
+2. **Continuous Synchronisation of Resources:** Running Flux in the management cluster will ensure the continuous synchronisation of the configuration
+3. **Consistent Deployments:** Define Sveltos ClusterProfiles to confidently deploy Kubernetes add-ons in matching clusters
+
+## How it works?
+
+We can store all the required Kubernetes resources in a Git repository and let Flux take care of the continuous synchronisation of those. Below, we demonstrate how to leverage Flux and Sveltos to automatically deploy a HelloWorld application to several managed clusters.
+
+- Example Repository: https://github.com/gianlucam76/kustomize/
+
+### Step 1: Configure Flux in the Management Cluster
+
+Run Flux in the management cluster and configure it to synchronise the Git repository which contains the HelloWorld manifests. Use a GitRepository resource similar to the below YAML definitions.
+
+```yaml
+---
+apiVersion: source.toolkit.fluxcd.io/v1
+kind: GitRepository
+metadata:
+ name: flux-system
+ namespace: flux-system
+spec:
+ interval: 1m0s
+ ref:
+ branch: main
+ secretRef:
+ name: flux-system
+ timeout: 60s
+ url: https://github.com/gianlucam76/kustomize.git
+```
+
+The above definition will look for updates of the main branch of the specified repository every minute.
+
+### Step 2: Create a Sveltos ClusterProfile
+
+Define a Sveltos ClusterProfile referencing to the `flux-system` `GitRepository` resource and define the HelloWorld directory as the source of the deployment. In the below YAML definition, application will get deployed on Cluster with the label selector set to *env=fv*.
+
+
+```yaml
+---
+apiVersion: config.projectsveltos.io/v1alpha1
+kind: ClusterProfile
+metadata:
+ name: deploy-helloworld-resources
+spec:
+ clusterSelector: env=fv
+ policyRefs:
+ - kind: GitRepository
+ name: flux-system
+ namespace: flux-system
+ path: ./helloWorld/
+ targetNamespace: eng
+```
+
+Whenever there is a change in the Git repository, Sveltos will leverage the Kustomize SDK to retrieve a list of resources to deploy to any cluster that matches the label selector `env=fv` in the `eng` namespace.
+
+**Note:** The GitRepository or Bucket content can also be a template. Sveltos will take the content of the files and instantiate them by the use of the data resources in the management cluster. 
+
+## More Resources
+
+For more information about the Sveltos and Flux integration, have a look [here](../addons/example_flux_sources.md).

mkdocs.yml

@@ -19,7 +19,7 @@ nav:
 - Use Cases:
  - Platform Administrators, Multicloud and Add-ons: 'use_cases/use_case_platform_admin_multicloud.md'
  - Platform Administrators and Multitenancy: 'use_cases/use_case_multitenancy.md'
- - Use Case 3: 'use_cases/use_case_3.md'
+ - Sveltos and Flux Integration: 'use_cases/use_case_flux_integration.md'
 - Installation:
  - Quick Start: 'install/quick_start.md'
  - Install: 'install/install.md'