Merge branch '56937-edit-knative-domain' into 'master'

Edit Knative domain after it has been deployed

Closes #56937

See merge request gitlab-org/gitlab-ce!25386

35 files changed, 958 insertions, 300 deletions

diff --git a/app/assets/javascripts/clusters/clusters_bundle.js b/app/assets/javascripts/clusters/clusters_bundle.js
index c59fac42038..388f674f643 100644
--- a/app/assets/javascripts/clusters/clusters_bundle.js
+++ b/app/assets/javascripts/clusters/clusters_bundle.js
@@ -36,6 +36,7 @@ export default class Clusters {
       installRunnerPath,
       installJupyterPath,
       installKnativePath,
+      updateKnativePath,
       installPrometheusPath,
       managePrometheusPath,
       hasRbac,
@@ -62,6 +63,7 @@ export default class Clusters {
       installPrometheusEndpoint: installPrometheusPath,
       installJupyterEndpoint: installJupyterPath,
       installKnativeEndpoint: installKnativePath,
+      updateKnativeEndpoint: updateKnativePath,
     });
 
     this.installApplication = this.installApplication.bind(this);
@@ -128,6 +130,8 @@ export default class Clusters {
     eventHub.$on('upgradeApplication', data => this.upgradeApplication(data));
     eventHub.$on('upgradeFailed', appId => this.upgradeFailed(appId));
     eventHub.$on('dismissUpgradeSuccess', appId => this.dismissUpgradeSuccess(appId));
+    eventHub.$on('saveKnativeDomain', data => this.saveKnativeDomain(data));
+    eventHub.$on('setKnativeHostname', data => this.setKnativeHostname(data));
   }
 
   removeListeners() {
@@ -136,6 +140,8 @@ export default class Clusters {
     eventHub.$off('upgradeApplication', this.upgradeApplication);
     eventHub.$off('upgradeFailed', this.upgradeFailed);
     eventHub.$off('dismissUpgradeSuccess', this.dismissUpgradeSuccess);
+    eventHub.$off('saveKnativeDomain');
+    eventHub.$off('setKnativeHostname');
   }
 
   initPolling() {
@@ -271,6 +277,18 @@ export default class Clusters {
     this.store.updateAppProperty(appId, 'requestStatus', null);
   }
 
+  saveKnativeDomain(data) {
+    const appId = data.id;
+    this.store.updateAppProperty(appId, 'status', APPLICATION_STATUS.UPDATING);
+    this.service.updateApplication(appId, data.params);
+  }
+
+  setKnativeHostname(data) {
+    const appId = data.id;
+    this.store.updateAppProperty(appId, 'isEditingHostName', true);
+    this.store.updateAppProperty(appId, 'hostname', data.hostname);
+  }
+
   destroy() {
     this.destroyed = true;
 
diff --git a/app/assets/javascripts/clusters/components/application_row.vue b/app/assets/javascripts/clusters/components/application_row.vue
index 5952e93b9a7..19e5ac1567d 100644
--- a/app/assets/javascripts/clusters/components/application_row.vue
+++ b/app/assets/javascripts/clusters/components/application_row.vue
@@ -191,14 +191,7 @@ export default {
       return this.status === APPLICATION_STATUS.UPDATE_ERRORED;
     },
     upgradeFailureDescription() {
-      return sprintf(
-        s__(
-          'ClusterIntegration|Something went wrong when upgrading %{title}. Please check the logs and try again.',
-        ),
-        {
-          title: this.title,
-        },
-      );
+      return s__('ClusterIntegration|Update failed. Please check the logs and try again.');
     },
     upgradeSuccessDescription() {
       return sprintf(s__('ClusterIntegration|%{title} upgraded successfully.'), {
@@ -210,9 +203,9 @@ export default {
       if (this.upgradeAvailable && !this.upgradeFailed && !this.isUpgrading) {
         label = s__('ClusterIntegration|Upgrade');
       } else if (this.isUpgrading) {
-        label = s__('ClusterIntegration|Upgrading');
+        label = s__('ClusterIntegration|Updating');
       } else if (this.upgradeFailed) {
-        label = s__('ClusterIntegration|Retry upgrade');
+        label = s__('ClusterIntegration|Retry update');
       }
 
       return label;
@@ -224,6 +217,14 @@ export default {
         (this.upgradeRequested && !this.upgradeSuccessful)
       );
     },
+    shouldShowUpgradeDetails() {
+      // This method only returns true when;
+      // Upgrade was successful OR Upgrade failed
+      //     AND new upgrade is unavailable AND version information is present.
+      return (
+        (this.upgradeSuccessful || this.upgradeFailed) && !this.upgradeAvailable && this.version
+      );
+    },
   },
   watch: {
     status() {
@@ -303,7 +304,7 @@ export default {
         </div>
 
         <div
-          v-if="(upgradeSuccessful || upgradeFailed) && !upgradeAvailable"
+          v-if="shouldShowUpgradeDetails"
           class="form-text text-muted label p-0 js-cluster-application-upgrade-details"
         >
           {{ versionLabel }}
diff --git a/app/assets/javascripts/clusters/components/applications.vue b/app/assets/javascripts/clusters/components/applications.vue
index 0cf187d4189..f74cd71de04 100644
--- a/app/assets/javascripts/clusters/components/applications.vue
+++ b/app/assets/javascripts/clusters/components/applications.vue
@@ -15,11 +15,14 @@ import { s__, sprintf } from '../../locale';
 import applicationRow from './application_row.vue';
 import clipboardButton from '../../vue_shared/components/clipboard_button.vue';
 import { CLUSTER_TYPE, APPLICATION_STATUS, INGRESS } from '../constants';
+import LoadingButton from '~/vue_shared/components/loading_button.vue';
+import eventHub from '~/clusters/event_hub';
 
 export default {
   components: {
     applicationRow,
     clipboardButton,
+    LoadingButton,
   },
   props: {
     type: {
@@ -173,16 +176,55 @@ export default {
     jupyterHostname() {
       return this.applications.jupyter.hostname;
     },
+    knative() {
+      return this.applications.knative;
+    },
     knativeInstalled() {
-      return this.applications.knative.status === APPLICATION_STATUS.INSTALLED;
+      return (
+        this.knative.status === APPLICATION_STATUS.INSTALLED ||
+        this.knativeUpgrading ||
+        this.knativeUpgradeFailed ||
+        this.knative.status === APPLICATION_STATUS.UPDATED
+      );
+    },
+    knativeUpgrading() {
+      return (
+        this.knative.status === APPLICATION_STATUS.UPDATING ||
+        this.knative.status === APPLICATION_STATUS.SCHEDULED
+      );
+    },
+    knativeUpgradeFailed() {
+      return this.knative.status === APPLICATION_STATUS.UPDATE_ERRORED;
     },
     knativeExternalIp() {
-      return this.applications.knative.externalIp;
+      return this.knative.externalIp;
+    },
+    canUpdateKnativeEndpoint() {
+      return this.knativeExternalIp && !this.knativeUpgradeFailed && !this.knativeUpgrading;
+    },
+    knativeHostname: {
+      get() {
+        return this.knative.hostname;
+      },
+      set(hostname) {
+        eventHub.$emit('setKnativeHostname', {
+          id: 'knative',
+          hostname,
+        });
+      },
     },
   },
   created() {
     this.helmInstallIllustration = helmInstallIllustration;
   },
+  methods: {
+    saveKnativeDomain() {
+      eventHub.$emit('saveKnativeDomain', {
+        id: 'knative',
+        params: { hostname: this.knative.hostname },
+      });
+    },
+  },
 };
 </script>
 
@@ -471,76 +513,88 @@ export default {
             }}
           </p>
 
-          <template v-if="knativeInstalled">
-            <div class="form-group">
-              <label for="knative-domainname">
-                {{ s__('ClusterIntegration|Knative Domain Name:') }}
-              </label>
-              <input
-                id="knative-domainname"
-                v-model="applications.knative.hostname"
-                type="text"
-                class="form-control js-domainname"
-                readonly
-              />
-            </div>
-          </template>
-          <template v-else-if="helmInstalled && rbac">
-            <div class="form-group">
-              <label for="knative-domainname">
-                {{ s__('ClusterIntegration|Knative Domain Name:') }}
-              </label>
-              <input
-                id="knative-domainname"
-                v-model="applications.knative.hostname"
-                type="text"
-                class="form-control js-domainname"
-              />
-            </div>
-          </template>
-          <template v-if="knativeInstalled">
-            <div class="form-group">
-              <label for="knative-ip-address">
-                {{ s__('ClusterIntegration|Knative IP Address:') }}
-              </label>
-              <div v-if="knativeExternalIp" class="input-group">
+          <div class="row">
+            <template v-if="knativeInstalled || (helmInstalled && rbac)">
+              <div
+                :class="{ 'col-md-6': knativeInstalled, 'col-12': helmInstalled && rbac }"
+                class="form-group col-sm-12 mb-0"
+              >
+                <label for="knative-domainname">
+                  <strong>
+                    {{ s__('ClusterIntegration|Knative Domain Name:') }}
+                  </strong>
+                </label>
                 <input
-                  id="knative-ip-address"
-                  :value="knativeExternalIp"
+                  id="knative-domainname"
+                  v-model="knativeHostname"
                   type="text"
-                  class="form-control js-ip-address"
-                  readonly
+                  class="form-control js-knative-domainname"
                 />
-                <span class="input-group-append">
-                  <clipboard-button
-                    :text="knativeExternalIp"
-                    :title="s__('ClusterIntegration|Copy Knative IP Address to clipboard')"
-                    class="input-group-text js-clipboard-btn"
+              </div>
+            </template>
+            <template v-if="knativeInstalled">
+              <div class="form-group col-sm-12 col-md-6 pl-md-0 mb-0 mt-3 mt-md-0">
+                <label for="knative-ip-address">
+                  <strong>
+                    {{ s__('ClusterIntegration|Knative Endpoint:') }}
+                  </strong>
+                </label>
+                <div v-if="knativeExternalIp" class="input-group">
+                  <input
+                    id="knative-ip-address"
+                    :value="knativeExternalIp"
+                    type="text"
+                    class="form-control js-knative-ip-address"
+                    readonly
                   />
-                </span>
+                  <span class="input-group-append">
+                    <clipboard-button
+                      :text="knativeExternalIp"
+                      :title="s__('ClusterIntegration|Copy Knative Endpoint to clipboard')"
+                      class="input-group-text js-knative-ip-clipboard-btn"
+                    />
+                  </span>
+                </div>
+                <input
+                  v-else
+                  type="text"
+                  class="form-control js-knative-ip-address"
+                  readonly
+                  value="?"
+                />
               </div>
-              <input v-else type="text" class="form-control js-ip-address" readonly value="?" />
-            </div>
 
-            <p v-if="!knativeExternalIp" class="settings-message js-no-ip-message">
-              {{
-                s__(`ClusterIntegration|The IP address is in
-              the process of being assigned. Please check your Kubernetes
-              cluster or Quotas on Google Kubernetes Engine if it takes a long time.`)
-              }}
-            </p>
+              <p class="form-text text-muted col-12">
+                {{
+                  s__(
+                    `ClusterIntegration|To access your application after deployment, point a wildcard DNS to the Knative Endpoint.`,
+                  )
+                }}
+                <a :href="ingressDnsHelpPath" target="_blank" rel="noopener noreferrer">
+                  {{ __('More information') }}
+                </a>
+              </p>
 
-            <p>
-              {{
-                s__(`ClusterIntegration|Point a wildcard DNS to this
-              generated IP address in order to access
-              your application after it has been deployed.`)
-              }}
-              <a :href="ingressDnsHelpPath" target="_blank" rel="noopener noreferrer">
-                {{ __('More information') }}
-              </a>
-            </p>
-          </template>
+              <p
+                v-if="!knativeExternalIp"
+                class="settings-message js-no-knative-ip-message mt-2 mr-3 mb-0 ml-3 "
+              >
+                {{
+                  s__(`ClusterIntegration|The IP address is in
+                the process of being assigned. Please check your Kubernetes
+                cluster or Quotas on Google Kubernetes Engine if it takes a long time.`)
+                }}
+              </p>
+
+              <button
+                v-if="canUpdateKnativeEndpoint"
+                class="btn btn-success js-knative-save-domain-button mt-3 ml-3"
+                @click="saveKnativeDomain"
+              >
+                {{ s__('ClusterIntegration|Save changes') }}
+              </button>
+            </template>
+          </div>
         </div>
       </application-row>
     </div>
diff --git a/app/assets/javascripts/clusters/services/clusters_service.js b/app/assets/javascripts/clusters/services/clusters_service.js
index 89dda4b7902..dea33ac44c5 100644
--- a/app/assets/javascripts/clusters/services/clusters_service.js
+++ b/app/assets/javascripts/clusters/services/clusters_service.js
@@ -12,6 +12,9 @@ export default class ClusterService {
       jupyter: this.options.installJupyterEndpoint,
       knative: this.options.installKnativeEndpoint,
     };
+    this.appUpdateEndpointMap = {
+      knative: this.options.updateKnativeEndpoint,
+    };
   }
 
   fetchData() {
@@ -22,6 +25,10 @@ export default class ClusterService {
     return axios.post(this.appInstallEndpointMap[appId], params);
   }
 
+  updateApplication(appId, params) {
+    return axios.patch(this.appUpdateEndpointMap[appId], params);
+  }
+
   static updateCluster(endpoint, data) {
     return axios.put(endpoint, data);
   }
diff --git a/app/assets/javascripts/clusters/stores/clusters_store.js b/app/assets/javascripts/clusters/stores/clusters_store.js
index d309678be27..3f03a8512fc 100644
--- a/app/assets/javascripts/clusters/stores/clusters_store.js
+++ b/app/assets/javascripts/clusters/stores/clusters_store.js
@@ -66,6 +66,7 @@ export default class ClusterStore {
           requestStatus: null,
           requestReason: null,
           hostname: null,
+          isEditingHostName: false,
           externalIp: null,
         },
       },
@@ -129,8 +130,10 @@ export default class ClusterStore {
             ? `jupyter.${this.state.applications.ingress.externalIp}.nip.io`
             : '');
       } else if (appId === KNATIVE) {
-        this.state.applications.knative.hostname =
-          serverAppEntry.hostname || this.state.applications.knative.hostname;
+        if (!this.state.applications.knative.isEditingHostName) {
+          this.state.applications.knative.hostname =
+            serverAppEntry.hostname || this.state.applications.knative.hostname;
+        }
         this.state.applications.knative.externalIp =
           serverAppEntry.external_ip || this.state.applications.knative.externalIp;
       } else if (appId === RUNNER) {
diff --git a/app/controllers/clusters/applications_controller.rb b/app/controllers/clusters/applications_controller.rb
index c4e7fc950f9..73c744efeba 100644
--- a/app/controllers/clusters/applications_controller.rb
+++ b/app/controllers/clusters/applications_controller.rb
@@ -3,26 +3,41 @@
 class Clusters::ApplicationsController < Clusters::BaseController
   before_action :cluster
   before_action :authorize_create_cluster!, only: [:create]
+  before_action :authorize_update_cluster!, only: [:update]
 
   def create
-    Clusters::Applications::CreateService
-      .new(@cluster, current_user, create_cluster_application_params)
-      .execute(request)
+    request_handler do
+      Clusters::Applications::CreateService
+        .new(@cluster, current_user, cluster_application_params)
+        .execute(request)
+    end
+  end
+
+  def update
+    request_handler do
+      Clusters::Applications::UpdateService
+        .new(@cluster, current_user, cluster_application_params)
+        .execute(request)
+    end
+  end
+
+  private
+
+  def request_handler
+    yield
 
     head :no_content
-  rescue Clusters::Applications::CreateService::InvalidApplicationError
+  rescue Clusters::Applications::BaseService::InvalidApplicationError
     render_404
   rescue StandardError
     head :bad_request
   end
 
-  private
-
   def cluster
     @cluster ||= clusterable.clusters.find(params[:id]) || render_404
   end
 
-  def create_cluster_application_params
+  def cluster_application_params
     params.permit(:application, :hostname, :email)
   end
 end
diff --git a/app/models/clusters/concerns/application_core.rb b/app/models/clusters/concerns/application_core.rb
index 683b45331f6..ee964fb7c93 100644
--- a/app/models/clusters/concerns/application_core.rb
+++ b/app/models/clusters/concerns/application_core.rb
@@ -30,6 +30,12 @@ module Clusters
           # Override if you need extra data synchronized
           # from K8s after installation
         end
+
+        def update_command
+          install_command.tap do |command|
+            command.version = version
+          end
+        end
       end
     end
   end
diff --git a/app/presenters/clusterable_presenter.rb b/app/presenters/clusterable_presenter.rb
index d94d9118eee..34bdf156623 100644
--- a/app/presenters/clusterable_presenter.rb
+++ b/app/presenters/clusterable_presenter.rb
@@ -44,6 +44,10 @@ class ClusterablePresenter < Gitlab::View::Presenter::Delegated
     raise NotImplementedError
   end
 
+  def update_applications_cluster_path(cluster, application)
+    raise NotImplementedError
+  end
+
   def cluster_path(cluster, params = {})
     raise NotImplementedError
   end
diff --git a/app/presenters/group_clusterable_presenter.rb b/app/presenters/group_clusterable_presenter.rb
index ef6bbc0d109..f5b0bb64487 100644
--- a/app/presenters/group_clusterable_presenter.rb
+++ b/app/presenters/group_clusterable_presenter.rb
@@ -14,6 +14,11 @@ class GroupClusterablePresenter < ClusterablePresenter
     install_applications_group_cluster_path(clusterable, cluster, application)
   end
 
+  override :update_applications_cluster_path
+  def update_applications_cluster_path(cluster, application)
+    update_applications_group_cluster_path(clusterable, cluster, application)
+  end
+
   override :cluster_path
   def cluster_path(cluster, params = {})
     group_cluster_path(clusterable, cluster, params)
diff --git a/app/presenters/project_clusterable_presenter.rb b/app/presenters/project_clusterable_presenter.rb
index 63e69b91b11..8661ee02b68 100644
--- a/app/presenters/project_clusterable_presenter.rb
+++ b/app/presenters/project_clusterable_presenter.rb
@@ -14,6 +14,11 @@ class ProjectClusterablePresenter < ClusterablePresenter
     install_applications_project_cluster_path(clusterable, cluster, application)
   end
 
+  override :update_applications_cluster_path
+  def update_applications_cluster_path(cluster, application)
+    update_applications_project_cluster_path(clusterable, cluster, application)
+  end
+
   override :cluster_path
   def cluster_path(cluster, params = {})
     project_cluster_path(clusterable, cluster, params)
diff --git a/app/services/clusters/applications/base_helm_service.rb b/app/services/clusters/applications/base_helm_service.rb
index 8a71730d5ec..c38b2656260 100644
--- a/app/services/clusters/applications/base_helm_service.rb
+++ b/app/services/clusters/applications/base_helm_service.rb
@@ -46,6 +46,10 @@ module Clusters
         @install_command ||= app.install_command
       end
 
+      def update_command
+        @update_command ||= app.update_command
+      end
+
       def upgrade_command(new_values = "")
         app.upgrade_command(new_values)
       end
diff --git a/app/services/clusters/applications/base_service.rb b/app/services/clusters/applications/base_service.rb
new file mode 100644
index 00000000000..cbd1cf03ae1
--- /dev/null
+++ b/app/services/clusters/applications/base_service.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+module Clusters
+  module Applications
+    class BaseService
+      InvalidApplicationError = Class.new(StandardError)
+
+      attr_reader :cluster, :current_user, :params
+
+      def initialize(cluster, user, params = {})
+        @cluster = cluster
+        @current_user = user
+        @params = params.dup
+      end
+
+      def execute(request)
+        instantiate_application.tap do |application|
+          if application.has_attribute?(:hostname)
+            application.hostname = params[:hostname]
+          end
+
+          if application.has_attribute?(:email)
+            application.email = params[:email]
+          end
+
+          if application.respond_to?(:oauth_application)
+            application.oauth_application = create_oauth_application(application, request)
+          end
+
+          worker = worker_class(application)
+
+          application.make_scheduled!
+
+          worker.perform_async(application.name, application.id)
+        end
+      end
+
+      protected
+
+      def worker_class(application)
+        raise NotImplementedError
+      end
+
+      def builders
+        raise NotImplementedError
+      end
+
+      def project_builders
+        raise NotImplementedError
+      end
+
+      def instantiate_application
+        builder.call(@cluster) || raise(InvalidApplicationError, "invalid application: #{application_name}")
+      end
+
+      def builder
+        builders[application_name] || raise(InvalidApplicationError, "invalid application: #{application_name}")
+      end
+
+      def application_name
+        params[:application]
+      end
+
+      def create_oauth_application(application, request)
+        oauth_application_params = {
+          name: params[:application],
+          redirect_uri: application.callback_url,
+          scopes: 'api read_user openid',
+          owner: current_user
+        }
+
+        ::Applications::CreateService.new(current_user, oauth_application_params).execute(request)
+      end
+    end
+  end
+end
diff --git a/app/services/clusters/applications/create_service.rb b/app/services/clusters/applications/create_service.rb
index 12f8c849d41..bd7c31bb981 100644
--- a/app/services/clusters/applications/create_service.rb
+++ b/app/services/clusters/applications/create_service.rb
@@ -2,47 +2,11 @@
 
 module Clusters
   module Applications
-    class CreateService
-      InvalidApplicationError = Class.new(StandardError)
-
-      attr_reader :cluster, :current_user, :params
-
-      def initialize(cluster, user, params = {})
-        @cluster = cluster
-        @current_user = user
-        @params = params.dup
-      end
-
-      def execute(request)
-        create_application.tap do |application|
-          if application.has_attribute?(:hostname)
-            application.hostname = params[:hostname]
-          end
-
-          if application.has_attribute?(:email)
-            application.email = params[:email]
-          end
-
-          if application.respond_to?(:oauth_application)
-            application.oauth_application = create_oauth_application(application, request)
-          end
-
-          worker = application.updateable? ? ClusterUpgradeAppWorker : ClusterInstallAppWorker
-
-          application.make_scheduled!
-
-          worker.perform_async(application.name, application.id)
-        end
-      end
-
+    class CreateService < Clusters::Applications::BaseService
       private
 
-      def create_application
-        builder.call(@cluster)
-      end
-
-      def builder
-        builders[application_name] || raise(InvalidApplicationError, "invalid application: #{application_name}")
+      def worker_class(application)
+        application.updateable? ? ClusterUpgradeAppWorker : ClusterInstallAppWorker
       end
 
       def builders
@@ -65,21 +29,6 @@ module Clusters
           "knative" => -> (cluster) { cluster.application_knative || cluster.build_application_knative }
         }
       end
-
-      def application_name
-        params[:application]
-      end
-
-      def create_oauth_application(application, request)
-        oauth_application_params = {
-          name: params[:application],
-          redirect_uri: application.callback_url,
-          scopes: 'api read_user openid',
-          owner: current_user
-        }
-
-        ::Applications::CreateService.new(current_user, oauth_application_params).execute(request)
-      end
     end
   end
 end
diff --git a/app/services/clusters/applications/install_service.rb b/app/services/clusters/applications/install_service.rb
index 5a65dc4ef59..5bd3623a558 100644
--- a/app/services/clusters/applications/install_service.rb
+++ b/app/services/clusters/applications/install_service.rb
@@ -6,19 +6,17 @@ module Clusters
       def execute
         return unless app.scheduled?
 
-        begin
-          app.make_installing!
-          helm_api.install(install_command)
+        app.make_installing!
+        helm_api.install(install_command)
 
-          ClusterWaitForAppInstallationWorker.perform_in(
-            ClusterWaitForAppInstallationWorker::INTERVAL, app.name, app.id)
-        rescue Kubeclient::HttpError => e
-          log_error(e)
-          app.make_errored!("Kubernetes error: #{e.error_code}")
-        rescue StandardError => e
-          log_error(e)
-          app.make_errored!("Can't start installation process.")
-        end
+        ClusterWaitForAppInstallationWorker.perform_in(
+          ClusterWaitForAppInstallationWorker::INTERVAL, app.name, app.id)
+      rescue Kubeclient::HttpError => e
+        log_error(e)
+        app.make_errored!("Kubernetes error: #{e.error_code}")
+      rescue StandardError => e
+        log_error(e)
+        app.make_errored!("Can't start installation process.")
       end
     end
   end
diff --git a/app/services/clusters/applications/patch_service.rb b/app/services/clusters/applications/patch_service.rb
new file mode 100644
index 00000000000..20c739af7a2
--- /dev/null
+++ b/app/services/clusters/applications/patch_service.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Clusters
+  module Applications
+    class PatchService < BaseHelmService
+      def execute
+        return unless app.scheduled?
+
+        app.make_updating!
+
+        helm_api.update(update_command)
+
+        ClusterWaitForAppInstallationWorker.perform_in(
+          ClusterWaitForAppInstallationWorker::INTERVAL, app.name, app.id)
+      rescue Kubeclient::HttpError => e
+        log_error(e)
+        app.make_update_errored!("Kubernetes error: #{e.error_code}")
+      rescue StandardError => e
+        log_error(e)
+        app.make_update_errored!("Can't start update process.")
+      end
+    end
+  end
+end
diff --git a/app/services/clusters/applications/update_service.rb b/app/services/clusters/applications/update_service.rb
new file mode 100644
index 00000000000..a9d4e609992
--- /dev/null
+++ b/app/services/clusters/applications/update_service.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module Clusters
+  module Applications
+    class UpdateService < Clusters::Applications::BaseService
+      private
+
+      def worker_class(application)
+        ClusterPatchAppWorker
+      end
+
+      def builders
+        {
+          "helm" => -> (cluster) { cluster.application_helm },
+          "ingress" => -> (cluster) { cluster.application_ingress },
+          "cert_manager" => -> (cluster) { cluster.application_cert_manager }
+        }.tap do |hash|
+          hash.merge!(project_builders) if cluster.project_type?
+        end
+      end
+
+      # These applications will need extra configuration to enable them to work
+      # with groups of projects
+      def project_builders
+        {
+          "prometheus" => -> (cluster) { cluster.application_prometheus },
+          "runner" => -> (cluster) { cluster.application_runner },
+          "jupyter" => -> (cluster) { cluster.application_jupyter },
+          "knative" => -> (cluster) { cluster.application_knative }
+        }
+      end
+    end
+  end
+end
diff --git a/app/views/clusters/clusters/show.html.haml b/app/views/clusters/clusters/show.html.haml
index 1ef76ef801e..7d381c6d4a6 100644
--- a/app/views/clusters/clusters/show.html.haml
+++ b/app/views/clusters/clusters/show.html.haml
@@ -15,6 +15,7 @@
   install_runner_path: clusterable.install_applications_cluster_path(@cluster, :runner),
   install_jupyter_path: clusterable.install_applications_cluster_path(@cluster, :jupyter),
   install_knative_path: clusterable.install_applications_cluster_path(@cluster, :knative),
+  update_knative_path: clusterable.update_applications_cluster_path(@cluster, :knative),
   toggle_status: @cluster.enabled? ? 'true': 'false',
   has_rbac: @cluster.platform_kubernetes_rbac? ? 'true': 'false',
   cluster_type: @cluster.cluster_type,
diff --git a/app/workers/all_queues.yml b/app/workers/all_queues.yml
index d86f654dd44..b2d88567e0e 100644
--- a/app/workers/all_queues.yml
+++ b/app/workers/all_queues.yml
@@ -23,6 +23,7 @@
 - cronjob:prune_web_hook_logs
 
 - gcp_cluster:cluster_install_app
+- gcp_cluster:cluster_patch_app
 - gcp_cluster:cluster_upgrade_app
 - gcp_cluster:cluster_provision
 - gcp_cluster:cluster_wait_for_app_installation
diff --git a/app/workers/cluster_patch_app_worker.rb b/app/workers/cluster_patch_app_worker.rb
new file mode 100644
index 00000000000..0549e81ed05
--- /dev/null
+++ b/app/workers/cluster_patch_app_worker.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class ClusterPatchAppWorker
+  include ApplicationWorker
+  include ClusterQueue
+  include ClusterApplications
+
+  def perform(app_name, app_id)
+    find_application(app_name, app_id) do |app|
+      Clusters::Applications::PatchService.new(app).execute
+    end
+  end
+end
diff --git a/changelogs/unreleased/56937-edit-knative-domain.yml b/changelogs/unreleased/56937-edit-knative-domain.yml
new file mode 100644
index 00000000000..7147a4e06b1
--- /dev/null
+++ b/changelogs/unreleased/56937-edit-knative-domain.yml
@@ -0,0 +1,5 @@
+---
+title: Edit Knative domain after it has been deployed
+merge_request: 25386
+author:
+type: added
diff --git a/config/routes.rb b/config/routes.rb
index 484e05114be..53c6225eff1 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -101,6 +101,7 @@ Rails.application.routes.draw do
       member do
         scope :applications do
           post '/:application', to: 'clusters/applications#create', as: :install_applications
+          patch '/:application', to: 'clusters/applications#update', as: :update_applications
         end
 
         get :cluster_status, format: :json
diff --git a/lib/gitlab/kubernetes/helm/install_command.rb b/lib/gitlab/kubernetes/helm/install_command.rb
index f931248b747..e33ba9305ce 100644
--- a/lib/gitlab/kubernetes/helm/install_command.rb
+++ b/lib/gitlab/kubernetes/helm/install_command.rb
@@ -7,7 +7,8 @@ module Gitlab
         include BaseCommand
         include ClientCommand
 
-        attr_reader :name, :files, :chart, :version, :repository, :preinstall, :postinstall
+        attr_reader :name, :files, :chart, :repository, :preinstall, :postinstall
+        attr_accessor :version
 
         def initialize(name:, chart:, files:, rbac:, version: nil, repository: nil, preinstall: nil, postinstall: nil)
           @name = name
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index d20ad666ba7..cfab870ce24 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -1698,7 +1698,7 @@ msgstr ""
 msgid "ClusterIntegration|Copy Jupyter Hostname to clipboard"
 msgstr ""
 
-msgid "ClusterIntegration|Copy Knative IP Address to clipboard"
+msgid "ClusterIntegration|Copy Knative Endpoint to clipboard"
 msgstr ""
 
 msgid "ClusterIntegration|Copy Kubernetes cluster name"
@@ -1821,7 +1821,7 @@ msgstr ""
 msgid "ClusterIntegration|Knative Domain Name:"
 msgstr ""
 
-msgid "ClusterIntegration|Knative IP Address:"
+msgid "ClusterIntegration|Knative Endpoint:"
 msgstr ""
 
 msgid "ClusterIntegration|Knative extends Kubernetes to provide a set of middleware components that are essential to build modern, source-centric, and container-based applications that can run anywhere: on premises, in the cloud, or even in a third-party data center."
@@ -1941,7 +1941,7 @@ msgstr ""
 msgid "ClusterIntegration|Request to begin installing failed"
 msgstr ""
 
-msgid "ClusterIntegration|Retry upgrade"
+msgid "ClusterIntegration|Retry update"
 msgstr ""
 
 msgid "ClusterIntegration|Save changes"
@@ -1986,9 +1986,6 @@ msgstr ""
 msgid "ClusterIntegration|Something went wrong on our end."
 msgstr ""
 
-msgid "ClusterIntegration|Something went wrong when upgrading %{title}. Please check the logs and try again."
-msgstr ""
-
 msgid "ClusterIntegration|Something went wrong while creating your Kubernetes cluster on Google Kubernetes Engine"
 msgstr ""
 
@@ -2007,12 +2004,21 @@ msgstr ""
 msgid "ClusterIntegration|This option will allow you to install applications on RBAC clusters."
 msgstr ""
 
+msgid "ClusterIntegration|To access your application after deployment, point a wildcard DNS to the Knative Endpoint."
+msgstr ""
+
 msgid "ClusterIntegration|Toggle Kubernetes cluster"
 msgstr ""
 
 msgid "ClusterIntegration|Token"
 msgstr ""
 
+msgid "ClusterIntegration|Update failed. Please check the logs and try again."
+msgstr ""
+
+msgid "ClusterIntegration|Updating"
+msgstr ""
+
 msgid "ClusterIntegration|Upgrade"
 msgstr ""
 
diff --git a/spec/controllers/groups/clusters/applications_controller_spec.rb b/spec/controllers/groups/clusters/applications_controller_spec.rb
index dd5263b077c..16a63536ea6 100644
--- a/spec/controllers/groups/clusters/applications_controller_spec.rb
+++ b/spec/controllers/groups/clusters/applications_controller_spec.rb
@@ -9,9 +9,25 @@ describe Groups::Clusters::ApplicationsController do
     Clusters::Cluster::APPLICATIONS[application]
   end
 
+  shared_examples 'a secure endpoint' do
+    it { expect { subject }.to be_allowed_for(:admin) }
+    it { expect { subject }.to be_allowed_for(:owner).of(group) }
+    it { expect { subject }.to be_allowed_for(:maintainer).of(group) }
+    it { expect { subject }.to be_denied_for(:developer).of(group) }
+    it { expect { subject }.to be_denied_for(:reporter).of(group) }
+    it { expect { subject }.to be_denied_for(:guest).of(group) }
+    it { expect { subject }.to be_denied_for(:user) }
+    it { expect { subject }.to be_denied_for(:external) }
+  end
+
+  let(:cluster) { create(:cluster, :group, :provided_by_gcp) }
+  let(:group) { cluster.group }
+
   describe 'POST create' do
-    let(:cluster) { create(:cluster, :group, :provided_by_gcp) }
-    let(:group) { cluster.group }
+    subject do
+      post :create, params: params.merge(group_id: group)
+    end
+
     let(:application) { 'helm' }
     let(:params) { { application: application, id: cluster.id } }
 
@@ -26,7 +42,7 @@ describe Groups::Clusters::ApplicationsController do
       it 'schedule an application installation' do
         expect(ClusterInstallAppWorker).to receive(:perform_async).with(application, anything).once
 
-        expect { go }.to change { current_application.count }
+        expect { subject }.to change { current_application.count }
         expect(response).to have_http_status(:no_content)
         expect(cluster.application_helm).to be_scheduled
       end
@@ -37,7 +53,7 @@ describe Groups::Clusters::ApplicationsController do
         end
 
         it 'return 404' do
-          expect { go }.not_to change { current_application.count }
+          expect { subject }.not_to change { current_application.count }
           expect(response).to have_http_status(:not_found)
         end
       end
@@ -46,9 +62,7 @@ describe Groups::Clusters::ApplicationsController do
         let(:application) { 'unkwnown-app' }
 
         it 'return 404' do
-          go
-
-          expect(response).to have_http_status(:not_found)
+          is_expected.to have_http_status(:not_found)
         end
       end
 
@@ -58,9 +72,7 @@ describe Groups::Clusters::ApplicationsController do
         end
 
         it 'returns 400' do
-          go
-
-          expect(response).to have_http_status(:bad_request)
+          is_expected.to have_http_status(:bad_request)
         end
       end
     end
@@ -70,18 +82,66 @@ describe Groups::Clusters::ApplicationsController do
         allow(ClusterInstallAppWorker).to receive(:perform_async)
       end
 
-      it { expect { go }.to be_allowed_for(:admin) }
-      it { expect { go }.to be_allowed_for(:owner).of(group) }
-      it { expect { go }.to be_allowed_for(:maintainer).of(group) }
-      it { expect { go }.to be_denied_for(:developer).of(group) }
-      it { expect { go }.to be_denied_for(:reporter).of(group) }
-      it { expect { go }.to be_denied_for(:guest).of(group) }
-      it { expect { go }.to be_denied_for(:user) }
-      it { expect { go }.to be_denied_for(:external) }
+      it_behaves_like 'a secure endpoint'
     end
+  end
 
-    def go
-      post :create, params: params.merge(group_id: group)
+  describe 'PATCH update' do
+    subject do
+      patch :update, params: params.merge(group_id: group)
+    end
+
+    let!(:application) { create(:clusters_applications_cert_managers, :installed, cluster: cluster) }
+    let(:application_name) { application.name }
+    let(:params) { { application: application_name, id: cluster.id, email: "new-email@example.com" } }
+
+    describe 'functionality' do
+      let(:user) { create(:user) }
+
+      before do
+        group.add_maintainer(user)
+        sign_in(user)
+      end
+
+      context "when cluster and app exists" do
+        it "schedules an application update" do
+          expect(ClusterPatchAppWorker).to receive(:perform_async).with(application.name, anything).once
+
+          is_expected.to have_http_status(:no_content)
+
+          expect(cluster.application_cert_manager).to be_scheduled
+        end
+      end
+
+      context 'when cluster do not exists' do
+        before do
+          cluster.destroy!
+        end
+
+        it { is_expected.to have_http_status(:not_found) }
+      end
+
+      context 'when application is unknown' do
+        let(:application_name) { 'unkwnown-app' }
+
+        it { is_expected.to have_http_status(:not_found) }
+      end
+
+      context 'when application is already scheduled' do
+        before do
+          application.make_scheduled!
+        end
+
+        it { is_expected.to have_http_status(:bad_request) }
+      end
+    end
+
+    describe 'security' do
+      before do
+        allow(ClusterPatchAppWorker).to receive(:perform_async)
+      end
+
+      it_behaves_like 'a secure endpoint'
     end
   end
 end
diff --git a/spec/controllers/projects/clusters/applications_controller_spec.rb b/spec/controllers/projects/clusters/applications_controller_spec.rb
index cb558259225..cd1a01f8acc 100644
--- a/spec/controllers/projects/clusters/applications_controller_spec.rb
+++ b/spec/controllers/projects/clusters/applications_controller_spec.rb
@@ -9,7 +9,22 @@ describe Projects::Clusters::ApplicationsController do
     Clusters::Cluster::APPLICATIONS[application]
   end
 
+  shared_examples 'a secure endpoint' do
+    it { expect { subject }.to be_allowed_for(:admin) }
+    it { expect { subject }.to be_allowed_for(:owner).of(project) }
+    it { expect { subject }.to be_allowed_for(:maintainer).of(project) }
+    it { expect { subject }.to be_denied_for(:developer).of(project) }
+    it { expect { subject }.to be_denied_for(:reporter).of(project) }
+    it { expect { subject }.to be_denied_for(:guest).of(project) }
+    it { expect { subject }.to be_denied_for(:user) }
+    it { expect { subject }.to be_denied_for(:external) }
+  end
+
   describe 'POST create' do
+    subject do
+      post :create, params: params.merge(namespace_id: project.namespace, project_id: project)
+    end
+
     let(:cluster) { create(:cluster, :project, :provided_by_gcp) }
     let(:project) { cluster.project }
     let(:application) { 'helm' }
@@ -26,7 +41,7 @@ describe Projects::Clusters::ApplicationsController do
       it 'schedule an application installation' do
         expect(ClusterInstallAppWorker).to receive(:perform_async).with(application, anything).once
 
-        expect { go }.to change { current_application.count }
+        expect { subject }.to change { current_application.count }
         expect(response).to have_http_status(:no_content)
         expect(cluster.application_helm).to be_scheduled
       end
@@ -37,7 +52,7 @@ describe Projects::Clusters::ApplicationsController do
         end
 
         it 'return 404' do
-          expect { go }.not_to change { current_application.count }
+          expect { subject }.not_to change { current_application.count }
           expect(response).to have_http_status(:not_found)
         end
       end
@@ -46,9 +61,7 @@ describe Projects::Clusters::ApplicationsController do
         let(:application) { 'unkwnown-app' }
 
         it 'return 404' do
-          go
-
-          expect(response).to have_http_status(:not_found)
+          is_expected.to have_http_status(:not_found)
         end
       end
 
@@ -58,9 +71,7 @@ describe Projects::Clusters::ApplicationsController do
         end
 
         it 'returns 400' do
-          go
-
-          expect(response).to have_http_status(:bad_request)
+          is_expected.to have_http_status(:bad_request)
         end
       end
     end
@@ -70,18 +81,68 @@ describe Projects::Clusters::ApplicationsController do
         allow(ClusterInstallAppWorker).to receive(:perform_async)
       end
 
-      it { expect { go }.to be_allowed_for(:admin) }
-      it { expect { go }.to be_allowed_for(:owner).of(project) }
-      it { expect { go }.to be_allowed_for(:maintainer).of(project) }
-      it { expect { go }.to be_denied_for(:developer).of(project) }
-      it { expect { go }.to be_denied_for(:reporter).of(project) }
-      it { expect { go }.to be_denied_for(:guest).of(project) }
-      it { expect { go }.to be_denied_for(:user) }
-      it { expect { go }.to be_denied_for(:external) }
+      it_behaves_like 'a secure endpoint'
     end
+  end
 
-    def go
-      post :create, params: params.merge(namespace_id: project.namespace, project_id: project)
+  describe 'PATCH update' do
+    subject do
+      patch :update, params: params.merge(namespace_id: project.namespace, project_id: project)
+    end
+
+    let(:cluster) { create(:cluster, :project, :provided_by_gcp) }
+    let(:project) { cluster.project }
+    let!(:application) { create(:clusters_applications_knative, :installed, cluster: cluster) }
+    let(:application_name) { application.name }
+    let(:params) { { application: application_name, id: cluster.id, hostname: "new.example.com" } }
+
+    describe 'functionality' do
+      let(:user) { create(:user) }
+
+      before do
+        project.add_maintainer(user)
+        sign_in(user)
+      end
+
+      context "when cluster and app exists" do
+        it "schedules an application update" do
+          expect(ClusterPatchAppWorker).to receive(:perform_async).with(application.name, anything).once
+
+          is_expected.to have_http_status(:no_content)
+
+          expect(cluster.application_knative).to be_scheduled
+        end
+      end
+
+      context 'when cluster do not exists' do
+        before do
+          cluster.destroy!
+        end
+
+        it { is_expected.to have_http_status(:not_found) }
+      end
+
+      context 'when application is unknown' do
+        let(:application_name) { 'unkwnown-app' }
+
+        it { is_expected.to have_http_status(:not_found) }
+      end
+
+      context 'when application is already scheduled' do
+        before do
+          application.make_scheduled!
+        end
+
+        it { is_expected.to have_http_status(:bad_request) }
+      end
+    end
+
+    describe 'security' do
+      before do
+        allow(ClusterPatchAppWorker).to receive(:perform_async)
+      end
+
+      it_behaves_like 'a secure endpoint'
     end
   end
 end
diff --git a/spec/features/projects/clusters/applications_spec.rb b/spec/features/projects/clusters/applications_spec.rb
index 2c8d014c36d..713e25cdcb2 100644
--- a/spec/features/projects/clusters/applications_spec.rb
+++ b/spec/features/projects/clusters/applications_spec.rb
@@ -17,7 +17,7 @@ describe 'Clusters Applications', :js do
     end
 
     context 'when cluster is being created' do
-      let(:cluster) { create(:cluster, :providing_by_gcp, projects: [project])}
+      let(:cluster) { create(:cluster, :providing_by_gcp, projects: [project]) }
 
       it 'user is unable to install applications' do
         page.within('.js-cluster-application-row-helm') do
@@ -28,9 +28,11 @@ describe 'Clusters Applications', :js do
     end
 
     context 'when cluster is created' do
-      let(:cluster) { create(:cluster, :provided_by_gcp, projects: [project])}
+      let(:cluster) { create(:cluster, :provided_by_gcp, projects: [project]) }
 
       it 'user can install applications' do
+        wait_for_requests
+
         page.within('.js-cluster-application-row-helm') do
           expect(page.find(:css, '.js-cluster-application-install-button')['disabled']).to be_nil
           expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Install')
@@ -44,6 +46,8 @@ describe 'Clusters Applications', :js do
           page.within('.js-cluster-application-row-helm') do
             page.find(:css, '.js-cluster-application-install-button').click
           end
+
+          wait_for_requests
         end
 
         it 'they see status transition' do
@@ -52,8 +56,6 @@ describe 'Clusters Applications', :js do
             expect(page.find(:css, '.js-cluster-application-install-button')['disabled']).to eq('true')
             expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installing')
 
-            wait_until_helm_created!
-
             Clusters::Cluster.last.application_helm.make_installing!
 
             # FE starts polling and update the buttons to "Installing"
@@ -76,7 +78,7 @@ describe 'Clusters Applications', :js do
         end
 
         context 'on an abac cluster' do
-          let(:cluster) { create(:cluster, :provided_by_gcp, :rbac_disabled, projects: [project])}
+          let(:cluster) { create(:cluster, :provided_by_gcp, :rbac_disabled, projects: [project]) }
 
           it 'should show info block and not be installable' do
             page.within('.js-cluster-application-row-knative') do
@@ -87,7 +89,7 @@ describe 'Clusters Applications', :js do
         end
 
         context 'on an rbac cluster' do
-          let(:cluster) { create(:cluster, :provided_by_gcp, projects: [project])}
+          let(:cluster) { create(:cluster, :provided_by_gcp, projects: [project]) }
 
           it 'should not show callout block and be installable' do
             page.within('.js-cluster-application-row-knative') do
@@ -95,6 +97,60 @@ describe 'Clusters Applications', :js do
               expect(page).to have_css('.js-cluster-application-install-button:not([disabled])')
             end
           end
+
+          describe 'when user clicks install button' do
+            def domainname_form_value
+              page.find('.js-knative-domainname').value
+            end
+
+            before do
+              allow(ClusterInstallAppWorker).to receive(:perform_async)
+              allow(ClusterWaitForIngressIpAddressWorker).to receive(:perform_in)
+              allow(ClusterWaitForIngressIpAddressWorker).to receive(:perform_async)
+
+              page.within('.js-cluster-application-row-knative') do
+                expect(page).to have_css('.js-cluster-application-install-button:not([disabled])')
+
+                page.find('.js-knative-domainname').set("domain.example.org")
+
+                click_button 'Install'
+
+                wait_for_requests
+
+                expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installing')
+
+                Clusters::Cluster.last.application_knative.make_installing!
+                Clusters::Cluster.last.application_knative.make_installed!
+                Clusters::Cluster.last.application_knative.update_attribute(:external_ip, '127.0.0.1')
+              end
+            end
+
+            it 'shows status transition' do
+              page.within('.js-cluster-application-row-knative') do
+                expect(domainname_form_value).to eq('domain.example.org')
+                expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installed')
+              end
+
+              expect(page).to have_content('Knative was successfully installed on your Kubernetes cluster')
+              expect(page).to have_css('.js-knative-save-domain-button'), exact_text: 'Save changes'
+            end
+
+            it 'can then update the domain' do
+              page.within('.js-cluster-application-row-knative') do
+                expect(ClusterPatchAppWorker).to receive(:perform_async)
+
+                expect(domainname_form_value).to eq('domain.example.org')
+
+                page.find('.js-knative-domainname').set("new.domain.example.org")
+
+                click_button 'Save changes'
+
+                wait_for_requests
+
+                expect(domainname_form_value).to eq('new.domain.example.org')
+              end
+            end
+          end
         end
       end
 
@@ -148,6 +204,8 @@ describe 'Clusters Applications', :js do
             page.within('.js-cluster-application-row-ingress') do
               expect(page).to have_css('.js-cluster-application-install-button:not([disabled])')
               page.find(:css, '.js-cluster-application-install-button').click
+
+              wait_for_requests
             end
           end
 
@@ -184,14 +242,4 @@ describe 'Clusters Applications', :js do
       end
     end
   end
-
-  def wait_until_helm_created!
-    retries = 0
-
-    while Clusters::Cluster.last.application_helm.nil?
-      raise "Timed out waiting for helm application to be created in DB" if (retries += 1) > 3
-
-      sleep(1)
-    end
-  end
 end
diff --git a/spec/javascripts/clusters/components/application_row_spec.js b/spec/javascripts/clusters/components/application_row_spec.js
index 8cb9713964e..a2dd4e93daf 100644
--- a/spec/javascripts/clusters/components/application_row_spec.js
+++ b/spec/javascripts/clusters/components/application_row_spec.js
@@ -230,7 +230,7 @@ describe('Application Row', () => {
       expect(upgradeBtn.innerHTML).toContain('Upgrade');
     });
 
-    it('has enabled "Retry upgrade" when APPLICATION_STATUS.UPDATE_ERRORED', () => {
+    it('has enabled "Retry update" when APPLICATION_STATUS.UPDATE_ERRORED', () => {
       vm = mountComponent(ApplicationRow, {
         ...DEFAULT_APPLICATION_STATE,
         status: APPLICATION_STATUS.UPDATE_ERRORED,
@@ -239,10 +239,10 @@ describe('Application Row', () => {
 
       expect(upgradeBtn).not.toBe(null);
       expect(vm.upgradeFailed).toBe(true);
-      expect(upgradeBtn.innerHTML).toContain('Retry upgrade');
+      expect(upgradeBtn.innerHTML).toContain('Retry update');
     });
 
-    it('has disabled "Retry upgrade" when APPLICATION_STATUS.UPDATING', () => {
+    it('has disabled "Updating" when APPLICATION_STATUS.UPDATING', () => {
       vm = mountComponent(ApplicationRow, {
         ...DEFAULT_APPLICATION_STATE,
         status: APPLICATION_STATUS.UPDATING,
@@ -251,7 +251,7 @@ describe('Application Row', () => {
 
       expect(upgradeBtn).not.toBe(null);
       expect(vm.isUpgrading).toBe(true);
-      expect(upgradeBtn.innerHTML).toContain('Upgrading');
+      expect(upgradeBtn.innerHTML).toContain('Updating');
     });
 
     it('clicking upgrade button emits event', () => {
@@ -295,7 +295,7 @@ describe('Application Row', () => {
 
       expect(failureMessage).not.toBe(null);
       expect(failureMessage.innerHTML).toContain(
-        'Something went wrong when upgrading GitLab Runner. Please check the logs and try again.',
+        'Update failed. Please check the logs and try again.',
       );
     });
   });
diff --git a/spec/javascripts/clusters/components/applications_spec.js b/spec/javascripts/clusters/components/applications_spec.js
index 14ef1193984..8daf0282184 100644
--- a/spec/javascripts/clusters/components/applications_spec.js
+++ b/spec/javascripts/clusters/components/applications_spec.js
@@ -1,7 +1,9 @@
 import Vue from 'vue';
 import applications from '~/clusters/components/applications.vue';
 import { CLUSTER_TYPE } from '~/clusters/constants';
+import eventHub from '~/clusters/event_hub';
 import mountComponent from 'spec/helpers/vue_mount_component_helper';
+import { APPLICATIONS_MOCK_STATE } from '../services/mock_data';
 
 describe('Applications', () => {
   let vm;
@@ -18,16 +20,8 @@ describe('Applications', () => {
   describe('Project cluster applications', () => {
     beforeEach(() => {
       vm = mountComponent(Applications, {
+        applications: APPLICATIONS_MOCK_STATE,
         type: CLUSTER_TYPE.PROJECT,
-        applications: {
-          helm: { title: 'Helm Tiller' },
-          ingress: { title: 'Ingress' },
-          cert_manager: { title: 'Cert-Manager' },
-          runner: { title: 'GitLab Runner' },
-          prometheus: { title: 'Prometheus' },
-          jupyter: { title: 'JupyterHub' },
-          knative: { title: 'Knative' },
-        },
       });
     });
 
@@ -64,15 +58,7 @@ describe('Applications', () => {
     beforeEach(() => {
       vm = mountComponent(Applications, {
         type: CLUSTER_TYPE.GROUP,
-        applications: {
-          helm: { title: 'Helm Tiller' },
-          ingress: { title: 'Ingress' },
-          cert_manager: { title: 'Cert-Manager' },
-          runner: { title: 'GitLab Runner' },
-          prometheus: { title: 'Prometheus' },
-          jupyter: { title: 'JupyterHub' },
-          knative: { title: 'Knative' },
-        },
+        applications: APPLICATIONS_MOCK_STATE,
       });
     });
 
@@ -111,17 +97,12 @@ describe('Applications', () => {
         it('renders ip address with a clipboard button', () => {
           vm = mountComponent(Applications, {
             applications: {
+              ...APPLICATIONS_MOCK_STATE,
               ingress: {
                 title: 'Ingress',
                 status: 'installed',
                 externalIp: '0.0.0.0',
               },
-              helm: { title: 'Helm Tiller' },
-              cert_manager: { title: 'Cert-Manager' },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
-              jupyter: { title: 'JupyterHub', hostname: '' },
-              knative: { title: 'Knative', hostname: '' },
             },
           });
 
@@ -137,16 +118,11 @@ describe('Applications', () => {
         it('renders an input text with a question mark and an alert text', () => {
           vm = mountComponent(Applications, {
             applications: {
+              ...APPLICATIONS_MOCK_STATE,
               ingress: {
                 title: 'Ingress',
                 status: 'installed',
               },
-              helm: { title: 'Helm Tiller' },
-              cert_manager: { title: 'Cert-Manager' },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
-              jupyter: { title: 'JupyterHub', hostname: '' },
-              knative: { title: 'Knative', hostname: '' },
             },
           });
 
@@ -160,15 +136,7 @@ describe('Applications', () => {
     describe('before installing', () => {
       it('does not render the IP address', () => {
         vm = mountComponent(Applications, {
-          applications: {
-            helm: { title: 'Helm Tiller' },
-            ingress: { title: 'Ingress' },
-            cert_manager: { title: 'Cert-Manager' },
-            runner: { title: 'GitLab Runner' },
-            prometheus: { title: 'Prometheus' },
-            jupyter: { title: 'JupyterHub', hostname: '' },
-            knative: { title: 'Knative', hostname: '' },
-          },
+          applications: APPLICATIONS_MOCK_STATE,
         });
 
         expect(vm.$el.textContent).not.toContain('Ingress IP Address');
@@ -181,17 +149,12 @@ describe('Applications', () => {
         it('renders email & allows editing', () => {
           vm = mountComponent(Applications, {
             applications: {
-              helm: { title: 'Helm Tiller', status: 'installed' },
-              ingress: { title: 'Ingress', status: 'installed', externalIp: '1.1.1.1' },
+              ...APPLICATIONS_MOCK_STATE,
               cert_manager: {
                 title: 'Cert-Manager',
                 email: 'before@example.com',
                 status: 'installable',
               },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
-              jupyter: { title: 'JupyterHub', hostname: '', status: 'installable' },
-              knative: { title: 'Knative', hostname: '', status: 'installable' },
             },
           });
 
@@ -204,17 +167,12 @@ describe('Applications', () => {
         it('renders email in readonly', () => {
           vm = mountComponent(Applications, {
             applications: {
-              helm: { title: 'Helm Tiller', status: 'installed' },
-              ingress: { title: 'Ingress', status: 'installed', externalIp: '1.1.1.1' },
+              ...APPLICATIONS_MOCK_STATE,
               cert_manager: {
                 title: 'Cert-Manager',
                 email: 'after@example.com',
                 status: 'installed',
               },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
-              jupyter: { title: 'JupyterHub', hostname: '', status: 'installable' },
-              knative: { title: 'Knative', hostname: '', status: 'installable' },
             },
           });
 
@@ -229,13 +187,12 @@ describe('Applications', () => {
         it('renders hostname active input', () => {
           vm = mountComponent(Applications, {
             applications: {
-              helm: { title: 'Helm Tiller', status: 'installed' },
-              ingress: { title: 'Ingress', status: 'installed', externalIp: '1.1.1.1' },
-              cert_manager: { title: 'Cert-Manager' },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
-              jupyter: { title: 'JupyterHub', hostname: '', status: 'installable' },
-              knative: { title: 'Knative', hostname: '', status: 'installable' },
+              ...APPLICATIONS_MOCK_STATE,
+              ingress: {
+                title: 'Ingress',
+                status: 'installed',
+                externalIp: '1.1.1.1',
+              },
             },
           });
 
@@ -247,13 +204,8 @@ describe('Applications', () => {
         it('does not render hostname input', () => {
           vm = mountComponent(Applications, {
             applications: {
-              helm: { title: 'Helm Tiller', status: 'installed' },
+              ...APPLICATIONS_MOCK_STATE,
               ingress: { title: 'Ingress', status: 'installed' },
-              cert_manager: { title: 'Cert-Manager' },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
-              jupyter: { title: 'JupyterHub', hostname: '', status: 'installable' },
-              knative: { title: 'Knative', hostname: '', status: 'installable' },
             },
           });
 
@@ -265,13 +217,9 @@ describe('Applications', () => {
         it('renders readonly input', () => {
           vm = mountComponent(Applications, {
             applications: {
-              helm: { title: 'Helm Tiller', status: 'installed' },
+              ...APPLICATIONS_MOCK_STATE,
               ingress: { title: 'Ingress', status: 'installed', externalIp: '1.1.1.1' },
-              cert_manager: { title: 'Cert-Manager' },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
               jupyter: { title: 'JupyterHub', status: 'installed', hostname: '' },
-              knative: { title: 'Knative', status: 'installed', hostname: '' },
             },
           });
 
@@ -282,15 +230,7 @@ describe('Applications', () => {
       describe('without ingress installed', () => {
         beforeEach(() => {
           vm = mountComponent(Applications, {
-            applications: {
-              helm: { title: 'Helm Tiller' },
-              ingress: { title: 'Ingress' },
-              cert_manager: { title: 'Cert-Manager' },
-              runner: { title: 'GitLab Runner' },
-              prometheus: { title: 'Prometheus' },
-              jupyter: { title: 'JupyterHub', status: 'not_installable' },
-              knative: { title: 'Knative' },
-            },
+            applications: APPLICATIONS_MOCK_STATE,
           });
         });
 
@@ -310,4 +250,77 @@ describe('Applications', () => {
       });
     });
   });
+
+  describe('Knative application', () => {
+    describe('when installed', () => {
+      describe('with ip address', () => {
+        const props = {
+          applications: {
+            ...APPLICATIONS_MOCK_STATE,
+            knative: {
+              title: 'Knative',
+              hostname: 'example.com',
+              status: 'installed',
+              externalIp: '1.1.1.1',
+            },
+          },
+        };
+        it('renders ip address with a clipboard button', () => {
+          vm = mountComponent(Applications, props);
+
+          expect(vm.$el.querySelector('.js-knative-ip-address').value).toEqual('1.1.1.1');
+
+          expect(
+            vm.$el
+              .querySelector('.js-knative-ip-clipboard-btn')
+              .getAttribute('data-clipboard-text'),
+          ).toEqual('1.1.1.1');
+        });
+
+        it('renders domain & allows editing', () => {
+          expect(vm.$el.querySelector('.js-knative-domainname').value).toEqual('example.com');
+          expect(vm.$el.querySelector('.js-knative-domainname').getAttribute('readonly')).toBe(
+            null,
+          );
+        });
+
+        it('renders an update/save Knative domain button', () => {
+          expect(vm.$el.querySelector('.js-knative-save-domain-button')).not.toBe(null);
+        });
+
+        it('emits event when clicking Save changes button', () => {
+          spyOn(eventHub, '$emit');
+          vm = mountComponent(Applications, props);
+
+          const saveButton = vm.$el.querySelector('.js-knative-save-domain-button');
+
+          saveButton.click();
+
+          expect(eventHub.$emit).toHaveBeenCalledWith('saveKnativeDomain', {
+            id: 'knative',
+            params: { hostname: 'example.com' },
+          });
+        });
+      });
+
+      describe('without ip address', () => {
+        it('renders an input text with a question mark and an alert text', () => {
+          vm = mountComponent(Applications, {
+            applications: {
+              ...APPLICATIONS_MOCK_STATE,
+              knative: {
+                title: 'Knative',
+                hostname: 'example.com',
+                status: 'installed',
+              },
+            },
+          });
+
+          expect(vm.$el.querySelector('.js-knative-ip-address').value).toEqual('?');
+
+          expect(vm.$el.querySelector('.js-no-knative-ip-message')).not.toBe(null);
+        });
+      });
+    });
+  });
 });
diff --git a/spec/javascripts/clusters/services/mock_data.js b/spec/javascripts/clusters/services/mock_data.js
index 3c3d9977ffb..3ace19c6401 100644
--- a/spec/javascripts/clusters/services/mock_data.js
+++ b/spec/javascripts/clusters/services/mock_data.js
@@ -115,4 +115,14 @@ const DEFAULT_APPLICATION_STATE = {
   requestReason: null,
 };
 
-export { CLUSTERS_MOCK_DATA, DEFAULT_APPLICATION_STATE };
+const APPLICATIONS_MOCK_STATE = {
+  helm: { title: 'Helm Tiller', status: 'installable' },
+  ingress: { title: 'Ingress', status: 'installable' },
+  cert_manager: { title: 'Cert-Manager', status: 'installable' },
+  runner: { title: 'GitLab Runner' },
+  prometheus: { title: 'Prometheus' },
+  jupyter: { title: 'JupyterHub', status: 'installable', hostname: '' },
+  knative: { title: 'Knative ', status: 'installable', hostname: '' },
+};
+
+export { CLUSTERS_MOCK_DATA, DEFAULT_APPLICATION_STATE, APPLICATIONS_MOCK_STATE };
diff --git a/spec/javascripts/clusters/stores/clusters_store_spec.js b/spec/javascripts/clusters/stores/clusters_store_spec.js
index 37a4d6614f6..09bcdf91d91 100644
--- a/spec/javascripts/clusters/stores/clusters_store_spec.js
+++ b/spec/javascripts/clusters/stores/clusters_store_spec.js
@@ -111,6 +111,7 @@ describe('Clusters Store', () => {
             requestStatus: null,
             requestReason: null,
             hostname: null,
+            isEditingHostName: false,
             externalIp: null,
           },
           cert_manager: {
diff --git a/spec/models/clusters/applications/knative_spec.rb b/spec/models/clusters/applications/knative_spec.rb
index 006b922ab27..4884a5927fb 100644
--- a/spec/models/clusters/applications/knative_spec.rb
+++ b/spec/models/clusters/applications/knative_spec.rb
@@ -66,9 +66,7 @@ describe Clusters::Applications::Knative do
     end
   end
 
-  describe '#install_command' do
-    subject { knative.install_command }
-
+  shared_examples 'a command' do
     it 'should be an instance of Helm::InstallCommand' do
       expect(subject).to be_an_instance_of(Gitlab::Kubernetes::Helm::InstallCommand)
     end
@@ -76,7 +74,6 @@ describe Clusters::Applications::Knative do
     it 'should be initialized with knative arguments' do
       expect(subject.name).to eq('knative')
       expect(subject.chart).to eq('knative/knative')
-      expect(subject.version).to eq('0.2.2')
       expect(subject.files).to eq(knative.files)
     end
 
@@ -98,6 +95,27 @@ describe Clusters::Applications::Knative do
     end
   end
 
+  describe '#install_command' do
+    subject { knative.install_command }
+
+    it 'should be initialized with latest version' do
+      expect(subject.version).to eq('0.2.2')
+    end
+
+    it_behaves_like 'a command'
+  end
+
+  describe '#update_command' do
+    let!(:current_installed_version) { knative.version = '0.1.0' }
+    subject { knative.update_command }
+
+    it 'should be initialized with current version' do
+      expect(subject.version).to eq(current_installed_version)
+    end
+
+    it_behaves_like 'a command'
+  end
+
   describe '#files' do
     let(:application) { knative }
     let(:values) { subject[:'values.yaml'] }
diff --git a/spec/presenters/group_clusterable_presenter_spec.rb b/spec/presenters/group_clusterable_presenter_spec.rb
index 205160742bf..fa77273f6aa 100644
--- a/spec/presenters/group_clusterable_presenter_spec.rb
+++ b/spec/presenters/group_clusterable_presenter_spec.rb
@@ -69,6 +69,14 @@ describe GroupClusterablePresenter do
     it { is_expected.to eq(install_applications_group_cluster_path(group, cluster, application)) }
   end
 
+  describe '#update_applications_cluster_path' do
+    let(:application) { :helm }
+
+    subject { presenter.update_applications_cluster_path(cluster, application) }
+
+    it { is_expected.to eq(update_applications_group_cluster_path(group, cluster, application)) }
+  end
+
   describe '#cluster_path' do
     subject { presenter.cluster_path(cluster) }
 
diff --git a/spec/presenters/project_clusterable_presenter_spec.rb b/spec/presenters/project_clusterable_presenter_spec.rb
index c50d90ae1e8..6786a84243f 100644
--- a/spec/presenters/project_clusterable_presenter_spec.rb
+++ b/spec/presenters/project_clusterable_presenter_spec.rb
@@ -69,6 +69,14 @@ describe ProjectClusterablePresenter do
     it { is_expected.to eq(install_applications_project_cluster_path(project, cluster, application)) }
   end
 
+  describe '#update_applications_cluster_path' do
+    let(:application) { :helm }
+
+    subject { presenter.update_applications_cluster_path(cluster, application) }
+
+    it { is_expected.to eq(update_applications_project_cluster_path(project, cluster, application)) }
+  end
+
   describe '#cluster_path' do
     subject { presenter.cluster_path(cluster) }
 
diff --git a/spec/services/clusters/applications/patch_service_spec.rb b/spec/services/clusters/applications/patch_service_spec.rb
new file mode 100644
index 00000000000..d4ee3243b84
--- /dev/null
+++ b/spec/services/clusters/applications/patch_service_spec.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Clusters::Applications::PatchService do
+  describe '#execute' do
+    let(:application) { create(:clusters_applications_knative, :scheduled) }
+    let!(:update_command) { application.update_command }
+    let(:service) { described_class.new(application) }
+    let(:helm_client) { instance_double(Gitlab::Kubernetes::Helm::Api) }
+
+    before do
+      allow(service).to receive(:update_command).and_return(update_command)
+      allow(service).to receive(:helm_api).and_return(helm_client)
+    end
+
+    context 'when there are no errors' do
+      before do
+        expect(helm_client).to receive(:update).with(update_command)
+        allow(ClusterWaitForAppInstallationWorker).to receive(:perform_in).and_return(nil)
+      end
+
+      it 'make the application updating' do
+        expect(application.cluster).not_to be_nil
+        service.execute
+
+        expect(application).to be_updating
+      end
+
+      it 'schedule async installation status check' do
+        expect(ClusterWaitForAppInstallationWorker).to receive(:perform_in).once
+
+        service.execute
+      end
+    end
+
+    context 'when kubernetes cluster communication fails' do
+      let(:error) { Kubeclient::HttpError.new(500, 'system failure', nil) }
+
+      before do
+        expect(helm_client).to receive(:update).with(update_command).and_raise(error)
+      end
+
+      it 'make the application errored' do
+        service.execute
+
+        expect(application).to be_update_errored
+        expect(application.status_reason).to match('Kubernetes error: 500')
+      end
+
+      it 'logs errors' do
+        expect(service.send(:logger)).to receive(:error).with(
+          {
+            exception: 'Kubeclient::HttpError',
+            message: 'system failure',
+            service: 'Clusters::Applications::PatchService',
+            app_id: application.id,
+            project_ids: application.cluster.project_ids,
+            group_ids: [],
+            error_code: 500
+          }
+        )
+
+        expect(Gitlab::Sentry).to receive(:track_acceptable_exception).with(
+          error,
+          extra: {
+            exception: 'Kubeclient::HttpError',
+            message: 'system failure',
+            service: 'Clusters::Applications::PatchService',
+            app_id: application.id,
+            project_ids: application.cluster.project_ids,
+            group_ids: [],
+            error_code: 500
+          }
+        )
+
+        service.execute
+      end
+    end
+
+    context 'a non kubernetes error happens' do
+      let(:application) { create(:clusters_applications_knative, :scheduled) }
+      let(:error) { StandardError.new('something bad happened') }
+
+      before do
+        expect(application).to receive(:make_updating!).once.and_raise(error)
+      end
+
+      it 'make the application errored' do
+        expect(helm_client).not_to receive(:update)
+
+        service.execute
+
+        expect(application).to be_update_errored
+        expect(application.status_reason).to eq("Can't start update process.")
+      end
+
+      it 'logs errors' do
+        expect(service.send(:logger)).to receive(:error).with(
+          {
+            exception: 'StandardError',
+            error_code: nil,
+            message: 'something bad happened',
+            service: 'Clusters::Applications::PatchService',
+            app_id: application.id,
+            project_ids: application.cluster.projects.pluck(:id),
+            group_ids: []
+          }
+        )
+
+        expect(Gitlab::Sentry).to receive(:track_acceptable_exception).with(
+          error,
+          extra: {
+            exception: 'StandardError',
+            error_code: nil,
+            message: 'something bad happened',
+            service: 'Clusters::Applications::PatchService',
+            app_id: application.id,
+            project_ids: application.cluster.projects.pluck(:id),
+            group_ids: []
+          }
+        )
+
+        service.execute
+      end
+    end
+  end
+end
diff --git a/spec/services/clusters/applications/update_service_spec.rb b/spec/services/clusters/applications/update_service_spec.rb
new file mode 100644
index 00000000000..2d299882af0
--- /dev/null
+++ b/spec/services/clusters/applications/update_service_spec.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Clusters::Applications::UpdateService do
+  include TestRequestHelpers
+
+  let(:cluster) { create(:cluster, :project, :provided_by_gcp) }
+  let(:user) { create(:user) }
+  let(:params) { { application: 'knative', hostname: 'udpate.example.com' } }
+  let(:service) { described_class.new(cluster, user, params) }
+
+  subject { service.execute(test_request) }
+
+  describe '#execute' do
+    before do
+      allow(ClusterPatchAppWorker).to receive(:perform_async)
+    end
+
+    context 'application is not installed' do
+      it 'raises Clusters::Applications::BaseService::InvalidApplicationError' do
+        expect(ClusterPatchAppWorker).not_to receive(:perform_async)
+
+        expect { subject }
+          .to raise_exception { Clusters::Applications::BaseService::InvalidApplicationError }
+          .and not_change { Clusters::Applications::Knative.count }
+          .and not_change { Clusters::Applications::Knative.with_status(:scheduled).count }
+      end
+    end
+
+    context 'application is installed' do
+      context 'application is schedulable' do
+        let!(:application) do
+          create(:clusters_applications_knative, status: 3, cluster: cluster)
+        end
+
+        it 'updates the application data' do
+          expect do
+            subject
+          end.to change { application.reload.hostname }.to(params[:hostname])
+        end
+
+        it 'makes application scheduled!' do
+          subject
+
+          expect(application.reload).to be_scheduled
+        end
+
+        it 'schedules ClusterPatchAppWorker' do
+          expect(ClusterPatchAppWorker).to receive(:perform_async)
+
+          subject
+        end
+      end
+
+      context 'application is not schedulable' do
+        let!(:application) do
+          create(:clusters_applications_knative, status: 4, cluster: cluster)
+        end
+
+        it 'raises StateMachines::InvalidTransition' do
+          expect(ClusterPatchAppWorker).not_to receive(:perform_async)
+
+          expect { subject }
+            .to raise_exception { StateMachines::InvalidTransition }
+            .and not_change { application.reload.hostname }
+            .and not_change { Clusters::Applications::Knative.with_status(:scheduled).count }
+        end
+      end
+    end
+  end
+end