Remove gitlab-managed-app namespace after helm is uninstalled

After uninstalling Helm we can also clear out everything
under the `gitlab-managed-apps` namespace as well as the
tiller-admin clusterrolebinding.

This contributes to https://gitlab.com/gitlab-org/gitlab/issues/26815

app/assets/javascripts/clusters/components/uninstall_application_confirmation_modal.vue

@@ -5,8 +5,14 @@ import trackUninstallButtonClickMixin from 'ee_else_ce/clusters/mixins/track_uni
 import { HELM, INGRESS, CERT_MANAGER, PROMETHEUS, RUNNER, KNATIVE, JUPYTER } from '../constants';
 
 const CUSTOM_APP_WARNING_TEXT = {
-  [HELM]: s__(
-    'ClusterIntegration|The associated Tiller pod will be deleted and cannot be restored.',
+  [HELM]: sprintf(
+    s__(
+      'ClusterIntegration|The associated Tiller pod, the %{gitlabManagedAppsNamespace} namespace, and all of its resources will be deleted and cannot be restored.',
+    ),
+    {
+      gitlabManagedAppsNamespace: '<code>gitlab-managed-apps</code>',
+    },
+    false,
   ),
   [INGRESS]: s__(
     'ClusterIntegration|The associated load balancer and IP will be deleted and cannot be restored.',
@@ -76,6 +82,7 @@ export default {
     :modal-id="modalId"
     :title="title"
     @ok="confirmUninstall()"
-    >{{ warningText }} {{ customAppWarningText }}</gl-modal
   >
+    {{ warningText }} <span v-html="customAppWarningText"></span>
+  </gl-modal>
 </template>

app/models/clusters/applications/helm.rb

@@ -68,6 +68,13 @@ module Clusters
         ca_key.present? && ca_cert.present?
       end
 
+      def post_uninstall
+        cluster.kubeclient.delete_namespace(Gitlab::Kubernetes::Helm::NAMESPACE)
+      rescue Kubeclient::ResourceNotFoundError
+        # we actually don't care if the namespace is not present
+        # since we want to delete it anyway.
+      end
+
       private
 
       def files

lib/gitlab/kubernetes/helm/reset_command.rb

@@ -18,7 +18,8 @@ module Gitlab
         def generate_script
           super + [
             reset_helm_command,
-            delete_tiller_replicaset
+            delete_tiller_replicaset,
+            delete_tiller_clusterrolebinding
           ].join("\n")
         end
 
@@ -43,6 +44,12 @@ module Gitlab
           Gitlab::Kubernetes::KubectlCmd.delete(*delete_args)
         end
 
+        def delete_tiller_clusterrolebinding
+          delete_args = %w[clusterrolebinding tiller-admin]
+
+          Gitlab::Kubernetes::KubectlCmd.delete(*delete_args)
+        end
+
         def reset_helm_command
           command = %w[helm reset] + optional_tls_flags
 

lib/gitlab/kubernetes/kube_client.rb

@@ -39,6 +39,7 @@ module Gitlab
         :get_secret,
         :get_service,
         :get_service_account,
+        :delete_namespace,
         :delete_pod,
         :create_config_map,
         :create_namespace,

locale/gitlab.pot

@@ -3703,7 +3703,7 @@ msgstr ""
 msgid "ClusterIntegration|The associated IP and all deployed services will be deleted and cannot be restored. Uninstalling Knative will also remove Istio from your cluster. This will not effect any other applications."
 msgstr ""
 
-msgid "ClusterIntegration|The associated Tiller pod will be deleted and cannot be restored."
+msgid "ClusterIntegration|The associated Tiller pod, the %{gitlabManagedAppsNamespace} namespace, and all of its resources will be deleted and cannot be restored."
 msgstr ""
 
 msgid "ClusterIntegration|The associated load balancer and IP will be deleted and cannot be restored."

spec/lib/gitlab/kubernetes/helm/reset_command_spec.rb

@@ -15,6 +15,7 @@ describe Gitlab::Kubernetes::Helm::ResetCommand do
       <<~EOS
       helm reset
       kubectl delete replicaset -n gitlab-managed-apps -l name\\=tiller
+      kubectl delete clusterrolebinding tiller-admin
       EOS
     end
   end
@@ -32,6 +33,7 @@ describe Gitlab::Kubernetes::Helm::ResetCommand do
         --tls-key /data/helm/helm/config/key.pem
         EOS1
           kubectl delete replicaset -n gitlab-managed-apps -l name\\=tiller
+          kubectl delete clusterrolebinding tiller-admin
         EOS2
       end
     end

spec/lib/gitlab/kubernetes/kube_client_spec.rb

@@ -162,6 +162,7 @@ describe Gitlab::Kubernetes::KubeClient do
       :get_secret,
       :get_service,
       :get_service_account,
+      :delete_namespace,
       :delete_pod,
       :create_config_map,
       :create_namespace,

spec/models/clusters/applications/helm_spec.rb

@@ -134,4 +134,14 @@ describe Clusters::Applications::Helm do
       end
     end
   end
+
+  describe '#post_uninstall' do
+    let(:helm) { create(:clusters_applications_helm, :installed) }
+
+    it do
+      expect(helm.cluster.kubeclient).to receive(:delete_namespace).with('gitlab-managed-apps')
+
+      helm.post_uninstall
+    end
+  end
 end