diff --git a/app/models/clusters/concerns/application_status.rb b/app/models/clusters/concerns/application_status.rb
index 7bb68d75224..c5711fd0b58 100644
--- a/app/models/clusters/concerns/application_status.rb
+++ b/app/models/clusters/concerns/application_status.rb
@@ -24,7 +24,7 @@ module Clusters
           end
 
           event :make_scheduled do
-            transition any - [:scheduled] => :scheduled
+            transition %i(installable errored) => :scheduled
           end
 
           before_transition any => [:scheduled] do |app_status, _|
diff --git a/app/services/clusters/applications/check_installation_progress_service.rb b/app/services/clusters/applications/check_installation_progress_service.rb
index 81306a2ff5b..1bd5dae0584 100644
--- a/app/services/clusters/applications/check_installation_progress_service.rb
+++ b/app/services/clusters/applications/check_installation_progress_service.rb
@@ -6,7 +6,7 @@ module Clusters
 
         case installation_phase
         when Gitlab::Kubernetes::Pod::SUCCEEDED
-          on_succeeded
+          finalize_installation
         when Gitlab::Kubernetes::Pod::FAILED
           on_failed
         else
@@ -18,14 +18,6 @@ module Clusters
 
       private
 
-      def on_succeeded
-        if app.make_installed
-          finalize_installation
-        else
-          app.make_errored!("Failed to update app record; #{app.errors}")
-        end
-      end
-
       def on_failed
         app.make_errored!(installation_errors || 'Installation silently failed')
         finalize_installation
@@ -34,6 +26,7 @@ module Clusters
       def check_timeout
         if Time.now.utc - app.updated_at.to_time.utc > ClusterWaitForAppInstallationWorker::TIMEOUT
           app.make_errored!('Installation timeouted')
+          finalize_installation
         else
           ClusterWaitForAppInstallationWorker.perform_in(
             ClusterWaitForAppInstallationWorker::INTERVAL, app.name, app.id)
diff --git a/app/services/clusters/applications/finalize_installation_service.rb b/app/services/clusters/applications/finalize_installation_service.rb
index 339d671c091..292c789b67b 100644
--- a/app/services/clusters/applications/finalize_installation_service.rb
+++ b/app/services/clusters/applications/finalize_installation_service.rb
@@ -4,13 +4,7 @@ module Clusters
       def execute
         helm_api.delete_installation_pod!(app)
 
-        app.make_errored!('Installation aborted') if aborted?
-      end
-
-      private
-
-      def aborted?
-        app.installing? || app.scheduled?
+        app.make_installed! if app.installing?
       end
     end
   end
diff --git a/app/services/clusters/applications/install_service.rb b/app/services/clusters/applications/install_service.rb
index 5ed0968a98a..4eba19a474e 100644
--- a/app/services/clusters/applications/install_service.rb
+++ b/app/services/clusters/applications/install_service.rb
@@ -5,14 +5,11 @@ module Clusters
         return unless app.scheduled?
 
         begin
+          app.make_installing!
           helm_api.install(app)
 
-          if app.make_installing
-            ClusterWaitForAppInstallationWorker.perform_in(
-              ClusterWaitForAppInstallationWorker::INTERVAL, app.name, app.id)
-          else
-            app.make_errored!("Failed to update app record; #{app.errors}")
-          end
+          ClusterWaitForAppInstallationWorker.perform_in(
+            ClusterWaitForAppInstallationWorker::INTERVAL, app.name, app.id)
         rescue KubeException => ke
           app.make_errored!("Kubernetes error: #{ke.message}")
         rescue StandardError
diff --git a/app/services/clusters/applications/schedule_installation_service.rb b/app/services/clusters/applications/schedule_installation_service.rb
index 17b3a09948d..eb8caa68ef7 100644
--- a/app/services/clusters/applications/schedule_installation_service.rb
+++ b/app/services/clusters/applications/schedule_installation_service.rb
@@ -2,15 +2,10 @@ module Clusters
   module Applications
     class ScheduleInstallationService < ::BaseService
       def execute
-        application = application_class.find_or_create_by!(cluster: cluster)
-
-        application.make_scheduled!
-        ClusterInstallAppWorker.perform_async(application.name, application.id)
-        true
-      rescue ActiveRecord::RecordInvalid
-        false
-      rescue StateMachines::InvalidTransition
-        false
+        application_class.find_or_create_by!(cluster: cluster).try do |application|
+          application.make_scheduled!
+          ClusterInstallAppWorker.perform_async(application.name, application.id)
+        end
       end
 
       private
diff --git a/spec/services/clusters/applications/check_installation_progress_service_spec.rb b/spec/services/clusters/applications/check_installation_progress_service_spec.rb
index c64c3a0c94c..fe04fac9613 100644
--- a/spec/services/clusters/applications/check_installation_progress_service_spec.rb
+++ b/spec/services/clusters/applications/check_installation_progress_service_spec.rb
@@ -3,20 +3,27 @@ require 'spec_helper'
 describe Clusters::Applications::CheckInstallationProgressService do
   RESCHEDULE_PHASES = Gitlab::Kubernetes::Pod::PHASES - [Gitlab::Kubernetes::Pod::SUCCEEDED, Gitlab::Kubernetes::Pod::FAILED].freeze
 
-  def mock_helm_api(phase, errors: nil)
-    expect(service).to receive(:installation_phase).once.and_return(phase)
-    expect(service).to receive(:installation_errors).once.and_return(errors) if errors.present?
+  let(:application) { create(:applications_helm, :installing) }
+  let(:service) { described_class.new(application) }
+  let(:phase) { Gitlab::Kubernetes::Pod::UNKNOWN }
+  let(:errors) { nil }
+
+  shared_examples 'a terminated installation' do
+    it 'finalize the installation' do
+      expect(service).to receive(:finalize_installation).once
+
+      service.execute
+    end
   end
 
-  shared_examples 'not yet completed phase' do |phase|
-    context "when the installation POD phase is #{phase}" do
-      before do
-        mock_helm_api(phase)
-      end
+  shared_examples 'a not yet terminated installation' do |a_phase|
+    let(:phase) { a_phase }
 
+    context "when phase is #{a_phase}" do
       context 'when not timeouted' do
         it 'reschedule a new check' do
           expect(ClusterWaitForAppInstallationWorker).to receive(:perform_in).once
+          expect(service).not_to receive(:finalize_installation)
 
           service.execute
 
@@ -28,6 +35,8 @@ describe Clusters::Applications::CheckInstallationProgressService do
       context 'when timeouted' do
         let(:application) { create(:applications_helm, :timeouted) }
 
+        it_behaves_like 'a terminated installation'
+
         it 'make the application errored' do
           expect(ClusterWaitForAppInstallationWorker).not_to receive(:perform_in)
 
@@ -40,36 +49,34 @@ describe Clusters::Applications::CheckInstallationProgressService do
     end
   end
 
+  before do
+    expect(service).to receive(:installation_phase).once.and_return(phase)
+
+    allow(service).to receive(:installation_errors).and_return(errors)
+    allow(service).to receive(:finalize_installation).and_return(nil)
+  end
+
   describe '#execute' do
-    let(:application) { create(:applications_helm, :installing) }
-    let(:service) { described_class.new(application) }
-
     context 'when installation POD succeeded' do
-      it 'make the application installed' do
-        mock_helm_api(Gitlab::Kubernetes::Pod::SUCCEEDED)
-        expect(service).to receive(:finalize_installation).once
+      let(:phase) { Gitlab::Kubernetes::Pod::SUCCEEDED }
 
-        service.execute
-
-        expect(application).to be_installed
-        expect(application.status_reason).to be_nil
-      end
+      it_behaves_like 'a terminated installation'
     end
 
     context 'when installation POD failed' do
-      let(:error_message) { 'test installation failed' }
+      let(:phase) { Gitlab::Kubernetes::Pod::FAILED }
+      let(:errors) { 'test installation failed' }
+
+      it_behaves_like 'a terminated installation'
 
       it 'make the application errored' do
-        mock_helm_api(Gitlab::Kubernetes::Pod::FAILED, errors: error_message)
-        expect(service).to receive(:finalize_installation).once
-
         service.execute
 
         expect(application).to be_errored
-        expect(application.status_reason).to eq(error_message)
+        expect(application.status_reason).to eq(errors)
       end
     end
 
-    RESCHEDULE_PHASES.each { |phase| it_behaves_like 'not yet completed phase', phase }
+    RESCHEDULE_PHASES.each { |phase| it_behaves_like 'a not yet terminated installation', phase }
   end
 end
diff --git a/spec/services/clusters/applications/finalize_installation_service_spec.rb b/spec/services/clusters/applications/finalize_installation_service_spec.rb
new file mode 100644
index 00000000000..08b7a80dfcd
--- /dev/null
+++ b/spec/services/clusters/applications/finalize_installation_service_spec.rb
@@ -0,0 +1,32 @@
+require 'spec_helper'
+
+describe Clusters::Applications::FinalizeInstallationService do
+  describe '#execute' do
+    let(:application) { create(:applications_helm, :installing) }
+    let(:service) { described_class.new(application) }
+
+    before do
+      expect_any_instance_of(Gitlab::Kubernetes::Helm).to receive(:delete_installation_pod!).with(application)
+    end
+
+    context 'when installation POD succeeded' do
+      it 'make the application installed' do
+        service.execute
+
+        expect(application).to be_installed
+        expect(application.status_reason).to be_nil
+      end
+    end
+
+    context 'when installation POD failed' do
+      let(:application) { create(:applications_helm, :errored) }
+
+      it 'make the application errored' do
+        service.execute
+
+        expect(application).to be_errored
+        expect(application.status_reason).not_to be_nil
+      end
+    end
+  end
+end
diff --git a/spec/services/clusters/applications/install_service_spec.rb b/spec/services/clusters/applications/install_service_spec.rb
new file mode 100644
index 00000000000..a646dac1cae
--- /dev/null
+++ b/spec/services/clusters/applications/install_service_spec.rb
@@ -0,0 +1,54 @@
+require 'spec_helper'
+
+describe Clusters::Applications::InstallService do
+  describe '#execute' do
+    let(:application) { create(:applications_helm, :scheduled) }
+    let(:service) { described_class.new(application) }
+
+    context 'when there are no errors' do
+      before do
+        expect_any_instance_of(Gitlab::Kubernetes::Helm).to receive(:install).with(application)
+        allow(ClusterWaitForAppInstallationWorker).to receive(:perform_in).and_return(nil)
+      end
+
+      it 'make the application installing' do
+        service.execute
+
+        expect(application).to be_installing
+      end
+
+      it 'schedule async installation status check' do
+        expect(ClusterWaitForAppInstallationWorker).to receive(:perform_in).once
+
+        service.execute
+      end
+    end
+
+    context 'when k8s cluster communication fails' do
+      before do
+        error = KubeException.new(500, 'system failure', nil)
+        expect_any_instance_of(Gitlab::Kubernetes::Helm).to receive(:install).with(application).and_raise(error)
+      end
+
+      it 'make the application errored' do
+        service.execute
+
+        expect(application).to be_errored
+        expect(application.status_reason).to match(/kubernetes error:/i)
+      end
+    end
+
+    context 'when application cannot be persisted' do
+      let(:application) { build(:applications_helm, :scheduled) }
+
+      it 'make the application errored' do
+        expect(application).to receive(:make_installing!).once.and_raise(ActiveRecord::RecordInvalid)
+        expect_any_instance_of(Gitlab::Kubernetes::Helm).not_to receive(:install)
+
+        service.execute
+
+        expect(application).to be_errored
+      end
+    end
+  end
+end
diff --git a/spec/services/clusters/applications/schedule_installation_service_spec.rb b/spec/services/clusters/applications/schedule_installation_service_spec.rb
new file mode 100644
index 00000000000..6ba587a41db
--- /dev/null
+++ b/spec/services/clusters/applications/schedule_installation_service_spec.rb
@@ -0,0 +1,55 @@
+require 'spec_helper'
+
+describe Clusters::Applications::ScheduleInstallationService do
+  def count_scheduled
+    application_class&.with_status(:scheduled)&.count || 0
+  end
+
+  shared_examples 'a failing service' do
+    it 'raise an exception' do
+      expect(ClusterInstallAppWorker).not_to receive(:perform_async)
+      count_before = count_scheduled
+
+      expect { service.execute }.to raise_error(StandardError)
+      expect(count_scheduled).to eq(count_before)
+    end
+  end
+
+  describe '#execute' do
+    let(:application_class) { Clusters::Applications::Helm }
+    let(:cluster) { create(:cluster, :project, :provided_by_gcp) }
+    let(:project) { cluster.project }
+    let(:service) { described_class.new(project, nil, cluster: cluster, application_class: application_class) }
+
+    it 'creates a new application' do
+      expect { service.execute }.to change { application_class.count }.by(1)
+    end
+
+    it 'make the application scheduled' do
+      expect(ClusterInstallAppWorker).to receive(:perform_async).with(application_class.application_name, kind_of(Numeric)).once
+
+      expect { service.execute }.to change { application_class.with_status(:scheduled).count }.by(1)
+    end
+
+    context 'when installation is already in progress' do
+      let(:application) { create(:applications_helm, :installing) }
+      let(:cluster) { application.cluster }
+
+      it_behaves_like 'a failing service'
+    end
+
+    context 'when application_class is nil' do
+      let(:application_class) { nil }
+
+      it_behaves_like 'a failing service'
+    end
+
+    context 'when application cannot be persisted' do
+      before do
+        expect_any_instance_of(application_class).to receive(:make_scheduled!).once.and_raise(ActiveRecord::RecordInvalid)
+      end
+
+      it_behaves_like 'a failing service'
+    end
+  end
+end