docs: deploy Keptn via ArgoCD

.github/actions/spelling/expect.txt

@@ -689,3 +689,4 @@ yourregistry
 GOGC
 otelcol
 serviceapp
+finalizer

docs/docs/installation/configuration/argocd.md

@@ -0,0 +1,50 @@
+---
+comments: true
+---
+
+# Deploy Keptn via ArgoCD
+
+Keptn can be deployed on your Kubernetes cluster
+via [ArgoCD](https://argoproj.github.io/cd/).
+
+## Before you begin
+
+To successfully deploy Keptn via ArgoCD, you need to
+have ArgoCD installed on your cluster.
+You can find the
+[installation instructions](https://argo-cd.readthedocs.io/en/stable/operator-manual/installation/)
+in the ArgoCD documentation.
+
+## Creating Argo Application
+
+After successfully installing ArgoCD, you need to create
+an Argo Application and define the
+repository containing Keptn helm charts:
+
+```yaml
+{% include "./assets/argo-app.yaml" %}
+```
+
+After applying the Application to your cluster,
+Argo will fetch the state of the linked repository
+and deploy the content via helm.
+
+You can access the ArgoCD UI to see that
+Keptn is up and running.
+
+![keptn argo](./assets/argo-keptn.png)
+
+> **Note**
+Please be aware, that you need to enable
+[cascading deletion](https://kubernetes.io/docs/concepts/architecture/garbage-collection/#cascading-deletion)
+of the application, which is disabled by default in ArgoCD.
+You can enable it by adding the deletion finalizers into your
+Argo Application, like it's done in the example above.
+More information about the deletion finalizers can be found
+[here](https://argo-cd.readthedocs.io/en/stable/user-guide/app_deletion/#about-the-deletion-finalizer).
+
+```yaml
+metadata:
+  finalizers:
+    - resources-finalizer.argocd.argoproj.io # enabling cascading deletion
+```

docs/docs/installation/configuration/assets/argo-app.yaml

@@ -0,0 +1,26 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: keptn
+  namespace: argocd
+  finalizers:
+    - resources-finalizer.argocd.argoproj.io # enabling cascading deletion
+spec:
+  project: default
+  source:
+    repoURL: 'https://charts.lifecycle.keptn.sh' # helm chart repository
+    chart: keptn # helm chart name
+    targetRevision: 0.5.1 # helm chart version - use latest available here
+    helm:
+      parameters:
+        - name: "commitID"
+          value: "$ARGOCD_APP_REVISION"
+  destination:
+    server: 'https://kubernetes.default.svc' # server where Keptn will be deployed
+    namespace: keptn-system # namespace where Keptn will be deployed
+  syncPolicy:
+    automated:
+      prune: true
+      selfHeal: true
+    syncOptions:
+      - CreateNamespace=true

docs/docs/installation/index.md

@@ -54,6 +54,10 @@ See
 [Running Keptn with vCluster](./configuration/vcluster.md)
 for more information.
 
+If you want to deploy Keptn via [ArgoCD](https://argoproj.github.io/cd/),
+refer to the [Deploying Keptn via ArgoCD](./configuration/argocd.md) section
+for more information.
+
 ## Basic installation
 
 Keptn is installed onto an existing Kubernetes cluster

docs/docs/installation/troubleshooting.md

@@ -48,24 +48,19 @@ More information can be found in the
 
 ## I have pending Pods after Keptn is uninstalled
 
-> **Note** This section particularly affects clusters managed by ArgoCD.
-
-If you have uninstalled Keptn and are now facing issues scheduling or deleting pods, follow these steps:
-
-ArgoCD does not delete various CRDs and webhooks, when uninstalling applications, causing lingering resources.
-
-### For cleanup instructions
-
-1. Install Keptn & CRDs w/ Argo
-2. Uninstall Keptn via Argo
-3. Cluster is frozen, Pods cannot be deleted or scheduled
-
-Trying to schedule a new pod results an `mpod.keptn.sh` error.
-
-Reason: Argo doesn't remove the CRDs and global objects (mutating webhooks) and the
-[default failurePolicy is to fail](https://github.com/keptn/lifecycle-toolkit/blob/650ecba95624ed3dc2bd61bf1f86578f450223a5/operator/config/webhook/manifests.yaml#L17).
-
-to get further information refer to this [issue](https://github.com/keptn/lifecycle-toolkit/issues/1828).
+> **Note** This section particularly affects clusters where
+Keptn was installed via ArgoCD.
+
+If you have uninstalled Keptn, originally installed via ArgoCD
+and are now facing issues scheduling or deleting pods for other applications,
+you probably didn't enable
+[cascading deletion](https://kubernetes.io/docs/concepts/architecture/garbage-collection/#cascading-deletion)
+of the application during installation, which is disabled by default in ArgoCD.
+
+To fix this problem, you need to install Keptn via ArgoCD again, with the use
+of `finalizers` in your Argo Application.
+For more information see the
+[Deploy Keptn via ArgoCD](./configuration/argocd.md) section for more information.
 
 ## I cannot see DORA metrics or OpenTelemetry traces
 

mkdocs.yml

@@ -121,6 +121,7 @@ nav:
               - How to structure your namespaces: docs/installation/configuration/namespace.md
               - vCluster installation: docs/installation/configuration/vcluster.md
               - Keptn + cert-manager.io: docs/installation/configuration/cert-manager.md
+              - Deploy Keptn via ArgoCD: docs/installation/configuration/argocd.md
           - Installation Tips and Tricks: docs/installation/tips-tricks.md
           - Troubleshooting Guide: docs/installation/troubleshooting.md
           - Kubernetes cluster: docs/installation/k8s.md