Merge branch '212229-move-features-to-core-multiple-kubernetes-clusters' into 'master'

[RUN AS-IF-FOSS] Move feature to core: "Multiple Kubernetes clusters"

Closes #212229

See merge request gitlab-org/gitlab!35094

app/helpers/clusters_helper.rb

 # frozen_string_literal: true
 
 module ClustersHelper
-  # EE overrides this
   def has_multiple_clusters?
-    false
+    true
   end
 
   def create_new_cluster_label(provider: nil)
@@ -95,5 +94,3 @@ module ClustersHelper
     can?(user, :admin_cluster, cluster)
   end
 end
-
-ClustersHelper.prepend_if_ee('EE::ClustersHelper')

app/models/clusters/cluster.rb

@@ -2,6 +2,7 @@
 
 module Clusters
   class Cluster < ApplicationRecord
+    prepend HasEnvironmentScope
     include Presentable
     include Gitlab::Utils::StrongMemoize
     include FromUnion
@@ -81,6 +82,7 @@ module Clusters
     validate :no_groups, unless: :group_type?
     validate :no_projects, unless: :project_type?
     validate :unique_management_project_environment_scope
+    validate :unique_environment_scope
 
     after_save :clear_reactive_cache!
 
@@ -354,6 +356,12 @@ module Clusters
       end
     end
 
+    def unique_environment_scope
+      if clusterable.present? && clusterable.clusters.where(environment_scope: environment_scope).where.not(id: id).exists?
+        errors.add(:environment_scope, 'cannot add duplicated environment scope')
+      end
+    end
+
     def managed_namespace(environment)
       Clusters::KubernetesNamespaceFinder.new(
         self,

app/models/concerns/deployment_platform.rb

 # frozen_string_literal: true
 
 module DeploymentPlatform
-  # EE would override this and utilize environment argument
   # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def deployment_platform(environment: nil)
     @deployment_platform ||= {}
@@ -20,16 +19,27 @@ module DeploymentPlatform
       find_instance_cluster_platform_kubernetes(environment: environment)
   end
 
-  # EE would override this and utilize environment argument
-  def find_platform_kubernetes_with_cte(_environment)
+  def find_platform_kubernetes_with_cte(environment)
+    if environment
+      ::Clusters::ClustersHierarchy.new(self, include_management_project: cluster_management_project_enabled?)
+        .base_and_ancestors
+        .enabled
+        .on_environment(environment, relevant_only: true)
+        .first&.platform_kubernetes
+    else
       Clusters::ClustersHierarchy.new(self, include_management_project: cluster_management_project_enabled?).base_and_ancestors
       .enabled.default_environment
       .first&.platform_kubernetes
     end
+  end
 
-  # EE would override this and utilize environment argument
   def find_instance_cluster_platform_kubernetes(environment: nil)
+    if environment
+      ::Clusters::Instance.new.clusters.enabled.on_environment(environment, relevant_only: true)
+      .first&.platform_kubernetes
+    else
       Clusters::Instance.new.clusters.enabled.default_environment
       .first&.platform_kubernetes
     end
+  end
 end

app/presenters/clusterable_presenter.rb

@@ -13,8 +13,7 @@ class ClusterablePresenter < Gitlab::View::Presenter::Delegated
   end
 
   def can_add_cluster?
-    can?(current_user, :add_cluster, clusterable) &&
-      (has_no_clusters? || multiple_clusters_available?)
+    can?(current_user, :add_cluster, clusterable)
   end
 
   def can_create_cluster?
@@ -81,17 +80,6 @@ class ClusterablePresenter < Gitlab::View::Presenter::Delegated
   def learn_more_link
     raise NotImplementedError
   end
-
-  private
-
-  # Overridden on EE module
-  def multiple_clusters_available?
-    false
-  end
-
-  def has_no_clusters?
-    clusterable.clusters.empty?
-  end
 end
 
 ClusterablePresenter.prepend_if_ee('EE::ClusterablePresenter')

app/services/clusters/create_service.rb

@@ -19,10 +19,6 @@ module Clusters
 
       cluster = Clusters::Cluster.new(cluster_params)
 
-      unless can_create_cluster?
-        cluster.errors.add(:base, _('Instance does not support multiple Kubernetes clusters'))
-      end
-
       validate_management_project_permissions(cluster)
 
       return cluster if cluster.errors.present?
@@ -55,16 +51,9 @@ module Clusters
       end
     end
 
-    # EE would override this method
-    def can_create_cluster?
-      clusterable.clusters.empty?
-    end
-
     def validate_management_project_permissions(cluster)
       Clusters::Management::ValidateManagementProjectPermissionsService.new(current_user)
         .execute(cluster, params[:management_project_id])
     end
   end
 end
-
-Clusters::CreateService.prepend_if_ee('EE::Clusters::CreateService')

ee/app/views/projects/clusters/_multiple_clusters_message.html.haml → app/views/clusters/clusters/_multiple_clusters_message.html.haml

-- autodevops_help_url = help_page_path('topics/autodevops/index.md', anchor: 'using-multiple-kubernetes-clusters-premium')
+- autodevops_help_url = help_page_path('topics/autodevops/index.md', anchor: 'using-multiple-kubernetes-clusters')
 - help_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe
 - help_link_end = '</a>'.html_safe
 

app/views/clusters/clusters/_sidebar.html.haml

@@ -5,4 +5,4 @@
 %p
   = clusterable.learn_more_link
 
-= render_if_exists 'clusters/multiple_clusters_message'
+= render 'clusters/clusters/multiple_clusters_message'

changelogs/unreleased/212229-move-features-to-core-multiple-kubernetes-clusters.yml

+---
+title: 'Multiple Kubernetes clusters now available in GitLab core'
+merge_request: 35094
+author:
+type: changed

doc/README.md

@@ -316,7 +316,7 @@ The following documentation relates to the DevOps **Configure** stage:
 | [GitLab ChatOps](ci/chatops/README.md)                                                                                             | Interact with CI/CD jobs through chat services.                           |
 | [Installing Applications](user/project/clusters/index.md#installing-applications)                                                  | Install Helm charts such as Ingress and Prometheus on Kubernetes.         |
 | [Mattermost slash commands](user/project/integrations/mattermost_slash_commands.md)                                                | Enable and use slash commands from within Mattermost.                     |
-| [Multiple Kubernetes Clusters](user/project/clusters/index.md#multiple-kubernetes-clusters-premium) **(PREMIUM)**                  | Associate more than one Kubernetes clusters to your project.              |
+| [Multiple Kubernetes Clusters](user/project/clusters/index.md#multiple-kubernetes-clusters)                                        | Associate more than one Kubernetes clusters to your project.              |
 | [Protected variables](ci/variables/README.md#protect-a-custom-variable)                                                            | Restrict variables to protected branches and tags.                        |
 | [Serverless](user/project/clusters/serverless/index.md)                                                                            | Run serverless workloads on Kubernetes.                                   |
 | [Slack slash commands](user/project/integrations/slack_slash_commands.md)                                                          | Enable and use slash commands from within Slack.                          |

doc/ci/variables/README.md

@@ -893,8 +893,8 @@ if [[ -d "/builds/gitlab-examples/ci-debug-trace/.git" ]]; then
 ++ CI_SERVER_VERSION_PATCH=0
 ++ export CI_SERVER_REVISION=f4cc00ae823
 ++ CI_SERVER_REVISION=f4cc00ae823
-++ export GITLAB_FEATURES=audit_events,burndown_charts,code_owners,contribution_analytics,description_diffs,elastic_search,group_bulk_edit,group_burndown_charts,group_webhooks,issuable_default_templates,issue_weights,jenkins_integration,ldap_group_sync,member_lock,merge_request_approvers,multiple_issue_assignees,multiple_ldap_servers,multiple_merge_request_assignees,protected_refs_for_users,push_rules,related_issues,repository_mirrors,repository_size_limit,scoped_issue_board,usage_quotas,visual_review_app,wip_limits,adjourned_deletion_for_projects_and_groups,admin_audit_log,auditor_user,batch_comments,blocking_merge_requests,board_assignee_lists,board_milestone_lists,ci_cd_projects,cluster_deployments,code_analytics,code_owner_approval_required,commit_committer_check,cross_project_pipelines,custom_file_templates,custom_file_templates_for_namespace,custom_project_templates,custom_prometheus_metrics,cycle_analytics_for_groups,db_load_balancing,default_project_deletion_protection,dependency_proxy,deploy_board,design_management,email_additional_text,extended_audit_events,external_authorization_service_api_management,feature_flags,file_locks,geo,github_project_service_integration,group_allowed_email_domains,group_project_templates,group_saml,issues_analytics,jira_dev_panel_integration,ldap_group_sync_filter,merge_pipelines,merge_request_performance_metrics,merge_trains,metrics_reports,multiple_approval_rules,multiple_clusters,multiple_group_issue_boards,object_storage,operations_dashboard,packages,productivity_analytics,project_aliases,protected_environments,reject_unsigned_commits,required_ci_templates,scoped_labels,service_desk,smartcard_auth,group_timelogs,type_of_work_analytics,unprotection_restrictions,ci_project_subscriptions,container_scanning,dast,dependency_scanning,epics,group_ip_restriction,incident_management,insights,license_management,personal_access_token_expiration_policy,pod_logs,prometheus_alerts,pseudonymizer,report_approver_rules,sast,security_dashboard,tracing,web_ide_terminal
-++ GITLAB_FEATURES=audit_events,burndown_charts,code_owners,contribution_analytics,description_diffs,elastic_search,group_bulk_edit,group_burndown_charts,group_webhooks,issuable_default_templates,issue_weights,jenkins_integration,ldap_group_sync,member_lock,merge_request_approvers,multiple_issue_assignees,multiple_ldap_servers,multiple_merge_request_assignees,protected_refs_for_users,push_rules,related_issues,repository_mirrors,repository_size_limit,scoped_issue_board,usage_quotas,visual_review_app,wip_limits,adjourned_deletion_for_projects_and_groups,admin_audit_log,auditor_user,batch_comments,blocking_merge_requests,board_assignee_lists,board_milestone_lists,ci_cd_projects,cluster_deployments,code_analytics,code_owner_approval_required,commit_committer_check,cross_project_pipelines,custom_file_templates,custom_file_templates_for_namespace,custom_project_templates,custom_prometheus_metrics,cycle_analytics_for_groups,db_load_balancing,default_project_deletion_protection,dependency_proxy,deploy_board,design_management,email_additional_text,extended_audit_events,external_authorization_service_api_management,feature_flags,file_locks,geo,github_project_service_integration,group_allowed_email_domains,group_project_templates,group_saml,issues_analytics,jira_dev_panel_integration,ldap_group_sync_filter,merge_pipelines,merge_request_performance_metrics,merge_trains,metrics_reports,multiple_approval_rules,multiple_clusters,multiple_group_issue_boards,object_storage,operations_dashboard,packages,productivity_analytics,project_aliases,protected_environments,reject_unsigned_commits,required_ci_templates,scoped_labels,service_desk,smartcard_auth,group_timelogs,type_of_work_analytics,unprotection_restrictions,ci_project_subscriptions,cluster_health,container_scanning,dast,dependency_scanning,epics,group_ip_restriction,incident_management,insights,license_management,personal_access_token_expiration_policy,pod_logs,prometheus_alerts,pseudonymizer,report_approver_rules,sast,security_dashboard,tracing,web_ide_terminal
+++ export GITLAB_FEATURES=audit_events,burndown_charts,code_owners,contribution_analytics,description_diffs,elastic_search,group_bulk_edit,group_burndown_charts,group_webhooks,issuable_default_templates,issue_weights,jenkins_integration,ldap_group_sync,member_lock,merge_request_approvers,multiple_issue_assignees,multiple_ldap_servers,multiple_merge_request_assignees,protected_refs_for_users,push_rules,related_issues,repository_mirrors,repository_size_limit,scoped_issue_board,usage_quotas,visual_review_app,wip_limits,adjourned_deletion_for_projects_and_groups,admin_audit_log,auditor_user,batch_comments,blocking_merge_requests,board_assignee_lists,board_milestone_lists,ci_cd_projects,cluster_deployments,code_analytics,code_owner_approval_required,commit_committer_check,cross_project_pipelines,custom_file_templates,custom_file_templates_for_namespace,custom_project_templates,custom_prometheus_metrics,cycle_analytics_for_groups,db_load_balancing,default_project_deletion_protection,dependency_proxy,deploy_board,design_management,email_additional_text,extended_audit_events,external_authorization_service_api_management,feature_flags,file_locks,geo,github_project_service_integration,group_allowed_email_domains,group_project_templates,group_saml,issues_analytics,jira_dev_panel_integration,ldap_group_sync_filter,merge_pipelines,merge_request_performance_metrics,merge_trains,metrics_reports,multiple_approval_rules,multiple_group_issue_boards,object_storage,operations_dashboard,packages,productivity_analytics,project_aliases,protected_environments,reject_unsigned_commits,required_ci_templates,scoped_labels,service_desk,smartcard_auth,group_timelogs,type_of_work_analytics,unprotection_restrictions,ci_project_subscriptions,container_scanning,dast,dependency_scanning,epics,group_ip_restriction,incident_management,insights,license_management,personal_access_token_expiration_policy,pod_logs,prometheus_alerts,pseudonymizer,report_approver_rules,sast,security_dashboard,tracing,web_ide_terminal
+++ GITLAB_FEATURES=audit_events,burndown_charts,code_owners,contribution_analytics,description_diffs,elastic_search,group_bulk_edit,group_burndown_charts,group_webhooks,issuable_default_templates,issue_weights,jenkins_integration,ldap_group_sync,member_lock,merge_request_approvers,multiple_issue_assignees,multiple_ldap_servers,multiple_merge_request_assignees,protected_refs_for_users,push_rules,related_issues,repository_mirrors,repository_size_limit,scoped_issue_board,usage_quotas,visual_review_app,wip_limits,adjourned_deletion_for_projects_and_groups,admin_audit_log,auditor_user,batch_comments,blocking_merge_requests,board_assignee_lists,board_milestone_lists,ci_cd_projects,cluster_deployments,code_analytics,code_owner_approval_required,commit_committer_check,cross_project_pipelines,custom_file_templates,custom_file_templates_for_namespace,custom_project_templates,custom_prometheus_metrics,cycle_analytics_for_groups,db_load_balancing,default_project_deletion_protection,dependency_proxy,deploy_board,design_management,email_additional_text,extended_audit_events,external_authorization_service_api_management,feature_flags,file_locks,geo,github_project_service_integration,group_allowed_email_domains,group_project_templates,group_saml,issues_analytics,jira_dev_panel_integration,ldap_group_sync_filter,merge_pipelines,merge_request_performance_metrics,merge_trains,metrics_reports,multiple_approval_rules,multiple_group_issue_boards,object_storage,operations_dashboard,packages,productivity_analytics,project_aliases,protected_environments,reject_unsigned_commits,required_ci_templates,scoped_labels,service_desk,smartcard_auth,group_timelogs,type_of_work_analytics,unprotection_restrictions,ci_project_subscriptions,cluster_health,container_scanning,dast,dependency_scanning,epics,group_ip_restriction,incident_management,insights,license_management,personal_access_token_expiration_policy,pod_logs,prometheus_alerts,pseudonymizer,report_approver_rules,sast,security_dashboard,tracing,web_ide_terminal
 ++ export CI_PROJECT_ID=17893
 ++ CI_PROJECT_ID=17893
 ++ export CI_PROJECT_NAME=ci-debug-trace

doc/topics/autodevops/index.md

@@ -248,11 +248,11 @@ TIP: **Tip:**
 Use the [blue-green deployment](../../ci/environments/incremental_rollouts.md#blue-green-deployment) technique
 to minimize downtime and risk.
 
-## Using multiple Kubernetes clusters **(PREMIUM)**
+## Using multiple Kubernetes clusters
 
 When using Auto DevOps, you can deploy different environments to
 different Kubernetes clusters, due to the 1:1 connection
-[existing between them](../../user/project/clusters/index.md#multiple-kubernetes-clusters-premium).
+[existing between them](../../user/project/clusters/index.md#multiple-kubernetes-clusters).
 
 The [Deploy Job template](https://gitlab.com/gitlab-org/gitlab/blob/master/lib/gitlab/ci/templates/Jobs/Deploy.gitlab-ci.yml)
 used by Auto DevOps currently defines 3 environment names:

doc/topics/autodevops/quick_start_guide.md

@@ -291,7 +291,7 @@ all within GitLab. Despite its automatic nature, Auto DevOps can also be configu
 and customized to fit your workflow. Here are some helpful resources for further reading:
 
 1. [Auto DevOps](index.md)
-1. [Multiple Kubernetes clusters](index.md#using-multiple-kubernetes-clusters-premium) **(PREMIUM)**
+1. [Multiple Kubernetes clusters](index.md#using-multiple-kubernetes-clusters)
 1. [Incremental rollout to production](customize.md#incremental-rollout-to-production-premium) **(PREMIUM)**
 1. [Disable jobs you don't need with environment variables](customize.md#environment-variables)
 1. [Use a static IP for your cluster](../../user/clusters/applications.md#using-a-static-ip)

doc/user/group/clusters/index.md

@@ -38,10 +38,11 @@ the project.
 In the case of sub-groups, GitLab uses the cluster of the closest ancestor group
 to the project, provided the cluster is not disabled.
 
-## Multiple Kubernetes clusters **(PREMIUM)**
+## Multiple Kubernetes clusters
 
-With [GitLab Premium](https://about.gitlab.com/pricing/premium/), you can associate
-more than one Kubernetes cluster to your group, and maintain different clusters
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/35094) to GitLab Core in 13.2.
+
+You can associate more than one Kubernetes cluster to your group, and maintain different clusters
 for different environments, such as development, staging, and production.
 
 When adding another cluster,
@@ -93,7 +94,7 @@ To clear the cache:
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/24580) in GitLab 11.8.
 
 Domains at the cluster level permit support for multiple domains
-per [multiple Kubernetes clusters](#multiple-kubernetes-clusters-premium). When specifying a domain,
+per [multiple Kubernetes clusters](#multiple-kubernetes-clusters) When specifying a domain,
 this will be automatically set as an environment variable (`KUBE_INGRESS_BASE_DOMAIN`) during
 the [Auto DevOps](../../../topics/autodevops/index.md) stages.
 

doc/user/project/clusters/index.md

@@ -64,11 +64,12 @@ to:
   (EKS) using GitLab's UI.
 - Add an integration to an existing cluster from any Kubernetes platform.
 
-### Multiple Kubernetes clusters **(PREMIUM)**
+### Multiple Kubernetes clusters
 
-> Introduced in [GitLab Premium](https://about.gitlab.com/pricing/) 10.3.
+> - Introduced in [GitLab Premium](https://about.gitlab.com/pricing/) 10.3
+> - [Moved](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/35094) to GitLab core in 13.2.
 
-With GitLab Premium, you can associate more than one Kubernetes cluster to your
+You can associate more than one Kubernetes cluster to your
 project. That way you can have different clusters for different environments,
 like dev, staging, production, and so on.
 

ee/app/helpers/ee/clusters_helper.rb

-# frozen_string_literal: true
-
-module EE
-  module ClustersHelper
-    extend ::Gitlab::Utils::Override
-
-    override :has_multiple_clusters?
-    def has_multiple_clusters?
-      clusterable.feature_available?(:multiple_clusters)
-    end
-  end
-end

ee/app/models/concerns/ee/deployment_platform.rb

-# frozen_string_literal: true
-
-module EE
-  module DeploymentPlatform
-    extend ::Gitlab::Utils::Override
-
-    override :find_platform_kubernetes_with_cte
-    def find_platform_kubernetes_with_cte(environment)
-      return super unless environment && feature_available?(:multiple_clusters)
-
-      ::Clusters::ClustersHierarchy.new(self, include_management_project: cluster_management_project_enabled?)
-        .base_and_ancestors
-        .enabled
-        .on_environment(environment, relevant_only: true)
-        .first&.platform_kubernetes
-    end
-
-    override :find_instance_cluster_platform_kubernetes
-    def find_instance_cluster_platform_kubernetes(environment: nil)
-      return super unless environment && feature_available?(:multiple_clusters)
-
-      ::Clusters::Instance.new.clusters.enabled.on_environment(environment, relevant_only: true)
-        .first&.platform_kubernetes
-    end
-  end
-end

ee/app/models/ee/clusters/cluster.rb

@@ -6,23 +6,12 @@ module EE
       extend ActiveSupport::Concern
 
       prepended do
-        prepend HasEnvironmentScope
         include UsageStatistics
-
-        validate :unique_environment_scope
       end
 
       def prometheus_adapter
         application_prometheus
       end
-
-      private
-
-      def unique_environment_scope
-        if clusterable.present? && clusterable.clusters.where(environment_scope: environment_scope).where.not(id: id).exists?
-          errors.add(:environment_scope, 'cannot add duplicated environment scope')
-        end
-      end
     end
   end
 end

ee/app/models/ee/project.rb

@@ -780,4 +780,3 @@ module EE
 end
 
 EE::Project.include_if_ee('::EE::GitlabRoutingHelper')
-EE::Project.include_if_ee('::EE::DeploymentPlatform')

ee/app/models/license.rb

@@ -89,7 +89,6 @@ class License < ApplicationRecord
     merge_trains
     metrics_reports
     multiple_approval_rules
-    multiple_clusters
     multiple_group_issue_boards
     object_storage
     operations_dashboard

ee/app/presenters/ee/clusterable_presenter.rb

@@ -2,8 +2,6 @@
 
 module EE
   module ClusterablePresenter
-    extend ::Gitlab::Utils::Override
-
     def metrics_cluster_path(cluster, params = {})
       raise NotImplementedError
     end
@@ -11,12 +9,5 @@ module EE
     def metrics_dashboard_path(cluster)
       raise NotImplementedError
     end
-
-    private
-
-    override :multiple_clusters_available?
-    def multiple_clusters_available?
-      clusterable.feature_available?(:multiple_clusters)
-    end
   end
 end

ee/app/services/ee/clusters/create_service.rb

-# frozen_string_literal: true
-
-module EE
-  module Clusters
-    module CreateService
-      extend ::Gitlab::Utils::Override
-
-      override :can_create_cluster?
-      def can_create_cluster?
-        super || clusterable.feature_available?(:multiple_clusters)
-      end
-    end
-  end
-end

ee/lib/ee/api/group_clusters.rb

-# frozen_string_literal: true
-
-module EE
-  module API
-    module GroupClusters
-      extend ActiveSupport::Concern
-
-      prepended do
-        helpers do
-          params :create_params_ee do
-            optional :environment_scope, default: '*', type: String, desc: 'The associated environment to the cluster'
-          end
-
-          params :update_params_ee do
-            optional :environment_scope, type: String, desc: 'The associated environment to the cluster'
-          end
-        end
-      end
-    end
-  end
-end

ee/lib/ee/api/project_clusters.rb

-# frozen_string_literal: true
-
-module EE
-  module API
-    module ProjectClusters
-      extend ActiveSupport::Concern
-
-      prepended do
-        helpers do
-          params :create_params_ee do
-            optional :environment_scope, default: '*', type: String, desc: 'The associated environment to the cluster'
-          end
-
-          params :update_params_ee do
-            optional :environment_scope, type: String, desc: 'The associated environment to the cluster'
-          end
-        end
-      end
-    end
-  end
-end

ee/spec/features/projects/clusters/gcp_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe 'Gcp Cluster', :js do
-  include GoogleApi::CloudPlatformHelpers
-
-  let(:project) { create(:project) }
-  let(:user) { create(:user) }
-
-  before do
-    project.add_maintainer(user)
-    gitlab_sign_in(user)
-    allow(Projects::ClustersController).to receive(:STATUS_POLLING_INTERVAL) { 100 }
-  end
-
-  context 'when a user has a licence to use multiple clusers' do
-    before do
-      stub_licensed_features(multiple_clusters: true)
-      visit project_clusters_path(project)
-
-      click_link 'Add Kubernetes cluster'
-      click_link 'Add existing cluster'
-    end
-
-    it 'user sees the "Environment scope" field' do
-      expect(page).to have_css('#cluster_environment_scope')
-    end
-  end
-end

ee/spec/features/projects/clusters_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe 'EE Clusters', :js do
-  include GoogleApi::CloudPlatformHelpers
-
-  let(:project) { create(:project) }
-  let(:user) { create(:user) }
-
-  before do
-    project.add_maintainer(user)
-    gitlab_sign_in(user)
-    stub_feature_flags(clusters_list_redesign: false)
-  end
-
-  context 'when user has a cluster' do
-    context 'when license has multiple clusters feature' do
-      before do
-        allow(License).to receive(:feature_available?).and_call_original
-        allow(License).to receive(:feature_available?).with(:multiple_clusters).and_return(true)
-        allow_any_instance_of(Clusters::Cluster).to receive(:retrieve_connection_status).and_return(:connected)
-      end
-
-      context 'when user adds an existing cluster' do
-        before do
-          create(:cluster, :provided_by_user, name: 'default-cluster', environment_scope: '*', projects: [project])
-          visit project_clusters_path(project)
-        end
-
-        it 'user sees a add cluster button ' do
-          expect(page).not_to have_selector('.js-add-cluster.readonly')
-          expect(page).to have_selector('.js-add-cluster')
-        end
-
-        context 'when user filled form with environment scope' do
-          before do
-            click_link 'Add Kubernetes cluster'
-            click_link 'Add existing cluster'
-            fill_in 'cluster_name', with: 'staging-cluster'
-            fill_in 'cluster_environment_scope', with: 'staging/*'
-            click_button 'Add Kubernetes cluster'
-          end
-
-          it 'user sees a cluster details page' do
-            expect(page.find_field('cluster[name]').value).to eq('staging-cluster')
-            expect(page.find_field('cluster[environment_scope]').value).to eq('staging/*')
-          end
-        end
-
-        context 'when user updates environment scope' do
-          before do
-            click_link 'default-cluster'
-            fill_in 'cluster_environment_scope', with: 'production/*'
-            within '.js-cluster-integration-form' do
-              click_button 'Save changes'
-            end
-          end
-
-          it 'user sees a cluster details page' do
-            expect(page.find_field('cluster[environment_scope]').value).to eq('production/*')
-          end
-        end
-
-        context 'when user updates duplicated environment scope' do
-          before do
-            click_link 'Add Kubernetes cluster'
-            click_link 'Add existing cluster'
-            fill_in 'cluster_name', with: 'staging-cluster'
-            fill_in 'cluster_environment_scope', with: '*'
-            fill_in 'cluster_platform_kubernetes_attributes_api_url', with: 'https://0.0.0.0'
-            fill_in 'cluster_platform_kubernetes_attributes_token', with: 'token'
-
-            click_button 'Add Kubernetes cluster'
-          end
-
-          it 'users sees an environment scope validation error' do
-            expect(page).to have_content('cannot add duplicated environment scope')
-          end
-        end
-      end
-
-      context 'when user adds an Google Kubernetes Engine cluster' do
-        before do
-          allow_any_instance_of(Projects::ClustersController)
-            .to receive(:token_in_session).and_return('token')
-          allow_any_instance_of(Projects::ClustersController)
-            .to receive(:expires_at_in_session).and_return(1.hour.since.to_i.to_s)
-
-          allow_any_instance_of(Projects::ClustersController).to receive(:authorize_google_project_billing)
-          allow_any_instance_of(Projects::ClustersController).to receive(:google_project_billing_status).and_return(true)
-
-          allow_any_instance_of(GoogleApi::CloudPlatform::Client)
-            .to receive(:projects_zones_clusters_create) do
-            OpenStruct.new(
-              self_link: 'projects/gcp-project-12345/zones/us-central1-a/operations/ope-123',
-              status: 'RUNNING'
-            )
-          end
-
-          allow(WaitForClusterCreationWorker).to receive(:perform_in).and_return(nil)
-
-          create(:cluster, :provided_by_gcp, name: 'default-cluster', environment_scope: '*', projects: [project])
-          visit project_clusters_path(project)
-        end
-
-        it 'user sees a add cluster button ' do
-          expect(page).not_to have_selector('.js-add-cluster.readonly')
-          expect(page).to have_selector('.js-add-cluster')
-        end
-
-        context 'when user filled form with environment scope' do
-          before do
-            click_link 'Add Kubernetes cluster'
-            click_link 'Create new cluster'
-            click_link 'Google GKE'
-
-            sleep 2 # wait for ajax
-            execute_script('document.querySelector(".js-gcp-project-id-dropdown input").setAttribute("type", "text")')
-            execute_script('document.querySelector(".js-gcp-zone-dropdown input").setAttribute("type", "text")')
-            execute_script('document.querySelector(".js-gcp-machine-type-dropdown input").setAttribute("type", "text")')
-            execute_script('document.querySelector(".js-gke-cluster-creation-submit").removeAttribute("disabled")')
-
-            fill_in 'cluster_name', with: 'staging-cluster'
-            fill_in 'cluster_environment_scope', with: 'staging/*'
-            fill_in 'cluster[provider_gcp_attributes][gcp_project_id]', with: 'gcp-project-123'
-            fill_in 'cluster[provider_gcp_attributes][zone]', with: 'us-central1-a'
-            fill_in 'cluster[provider_gcp_attributes][machine_type]', with: 'n1-standard-2'
-            click_button 'Create Kubernetes cluster'
-
-            # The frontend won't show the details until the cluster is
-            # created, and we don't want to make calls out to GCP.
-            provider = Clusters::Cluster.last.provider
-            provider.make_created
-          end
-
-          it 'user sees a cluster details page' do
-            expect(page).to have_content('GitLab Integration')
-            expect(page.find_field('cluster[environment_scope]').value).to eq('staging/*')
-          end
-        end
-
-        context 'when user updates environment scope' do
-          before do
-            click_link 'default-cluster'
-            fill_in 'cluster_environment_scope', with: 'production/*'
-            within ".js-cluster-integration-form" do
-              click_button 'Save changes'
-            end
-          end
-
-          it 'user sees a cluster details page' do
-            expect(page.find_field('cluster[environment_scope]').value).to eq('production/*')
-          end
-        end
-
-        context 'when user updates duplicated environment scope' do
-          before do
-            click_link 'Add Kubernetes cluster'
-            click_link 'Create new cluster'
-            click_link 'Google GKE'
-
-            sleep 2 # wait for ajax
-            execute_script('document.querySelector(".js-gcp-project-id-dropdown input").setAttribute("type", "text")')
-            execute_script('document.querySelector(".js-gcp-zone-dropdown input").setAttribute("type", "text")')
-            execute_script('document.querySelector(".js-gcp-machine-type-dropdown input").setAttribute("type", "text")')
-            execute_script('document.querySelector(".js-gke-cluster-creation-submit").removeAttribute("disabled")')
-
-            fill_in 'cluster_name', with: 'staging-cluster'
-            fill_in 'cluster_environment_scope', with: '*'
-            fill_in 'cluster[provider_gcp_attributes][gcp_project_id]', with: 'gcp-project-123'
-            fill_in 'cluster[provider_gcp_attributes][zone]', with: 'us-central1-a'
-            fill_in 'cluster[provider_gcp_attributes][machine_type]', with: 'n1-standard-2'
-            click_button 'Create Kubernetes cluster'
-          end
-
-          it 'users sees an environment scope validation error' do
-            expect(page).to have_content('cannot add duplicated environment scope')
-          end
-        end
-      end
-    end
-
-    context 'when license does not have multiple clusters feature' do
-      before do
-        allow(License).to receive(:feature_available?).and_call_original
-        allow(License).to receive(:feature_available?).with(:multiple_clusters).and_return(false)
-        create(:cluster, :provided_by_user, name: 'default-cluster', environment_scope: '*', projects: [project])
-      end
-
-      context 'when user visits cluster index page' do
-        before do
-          visit project_clusters_path(project)
-        end
-
-        it 'user sees a disabled add cluster button ' do
-          expect(page).to have_selector('.js-add-cluster.disabled')
-        end
-      end
-    end
-  end
-end

ee/spec/helpers/ee/clusters_helper_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe ClustersHelper do
-  shared_examples 'feature availablilty' do |feature|
-    before do
-      # clusterable is provided as a `helper_method`
-      allow(helper).to receive(:clusterable).and_return(clusterable)
-
-      expect(clusterable)
-        .to receive(:feature_available?)
-        .with(feature)
-        .and_return(feature_available)
-    end
-
-    context 'feature unavailable' do
-      let(:feature_available) { true }
-
-      it { is_expected.to be_truthy }
-    end
-
-    context 'feature available' do
-      let(:feature_available) { false }
-
-      it { is_expected.to be_falsey }
-    end
-  end
-
-  describe '#has_multiple_clusters?' do
-    subject { helper.has_multiple_clusters? }
-
-    context 'project level' do
-      let(:clusterable) { instance_double(Project) }
-
-      it_behaves_like 'feature availablilty', :multiple_clusters
-    end
-
-    context 'group level' do
-      let(:clusterable) { instance_double(Group) }
-
-      it_behaves_like 'feature availablilty', :multiple_clusters
-    end
-  end
-end

ee/spec/models/concerns/ee/deployment_platform_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe EE::DeploymentPlatform do
-  describe '#deployment_platform' do
-    let(:group) { create(:group) }
-    let(:project) { create(:project, group: group) }
-
-    shared_examples 'matching environment scope' do
-      context 'when multiple clusters license is available' do
-        before do
-          stub_licensed_features(multiple_clusters: true)
-        end
-
-        it 'returns environment specific cluster' do
-          is_expected.to eq(cluster.platform_kubernetes)
-        end
-      end
-
-      context 'when multiple clusters licence is unavailable' do
-        before do
-          stub_licensed_features(multiple_clusters: false)
-        end
-
-        it 'returns a kubernetes platform' do
-          is_expected.not_to eq(cluster.platform_kubernetes)
-          is_expected.to be_kind_of(Clusters::Platforms::Kubernetes)
-        end
-      end
-    end
-
-    shared_examples 'not matching environment scope' do
-      context 'when multiple clusters license is available' do
-        before do
-          stub_licensed_features(multiple_clusters: true)
-        end
-
-        it 'returns default cluster' do
-          is_expected.to eq(default_cluster.platform_kubernetes)
-        end
-      end
-
-      context 'when multiple clusters license is unavailable' do
-        before do
-          stub_licensed_features(multiple_clusters: false)
-        end
-
-        it 'returns default cluster' do
-          is_expected.to eq(default_cluster.platform_kubernetes)
-        end
-      end
-    end
-
-    context 'multiple clusters use the same management project' do
-      let(:management_project) { create(:project, group: group) }
-
-      let!(:default_cluster) do
-        create(:cluster_for_group, groups: [group], environment_scope: '*', management_project: management_project)
-      end
-
-      let!(:cluster) do
-        create(:cluster_for_group, groups: [group], environment_scope: 'review/*', management_project: management_project)
-      end
-
-      let(:environment) { 'review/name' }
-
-      subject { management_project.deployment_platform(environment: environment) }
-
-      it_behaves_like 'matching environment scope'
-    end
-
-    context 'when project does not have a cluster but has group clusters' do
-      let!(:default_cluster) do
-        create(:cluster, :provided_by_user,
-               cluster_type: :group_type, groups: [group], environment_scope: '*')
-      end
-
-      let!(:cluster) do
-        create(:cluster, :provided_by_user,
-               cluster_type: :group_type, environment_scope: 'review/*', groups: [group])
-      end
-
-      let(:environment) { 'review/name' }
-
-      subject { project.deployment_platform(environment: environment) }
-
-      context 'when environment scope is exactly matched' do
-        before do
-          cluster.update!(environment_scope: 'review/name')
-        end
-
-        it_behaves_like 'matching environment scope'
-      end
-
-      context 'when environment scope is matched by wildcard' do
-        before do
-          cluster.update!(environment_scope: 'review/*')
-        end
-
-        it_behaves_like 'matching environment scope'
-      end
-
-      context 'when environment scope does not match' do
-        before do
-          cluster.update!(environment_scope: 'review/*/special')
-        end
-
-        it_behaves_like 'not matching environment scope'
-      end
-
-      context 'when group belongs to a parent group' do
-        let(:parent_group) { create(:group) }
-        let(:group) { create(:group, parent: parent_group) }
-
-        context 'when parent_group has a cluster with default scope' do
-          let!(:parent_group_cluster) do
-            create(:cluster, :provided_by_user,
-                   cluster_type: :group_type, environment_scope: '*', groups: [parent_group])
-          end
-
-          it_behaves_like 'matching environment scope'
-        end
-
-        context 'when parent_group has a cluster that is an exact match' do
-          let!(:parent_group_cluster) do
-            create(:cluster, :provided_by_user,
-                   cluster_type: :group_type, environment_scope: 'review/name', groups: [parent_group])
-          end
-
-          it_behaves_like 'matching environment scope'
-        end
-      end
-    end
-
-    context 'with instance clusters' do
-      let!(:default_cluster) do
-        create(:cluster, :provided_by_user, :instance, environment_scope: '*')
-      end
-
-      let!(:cluster) do
-        create(:cluster, :provided_by_user, :instance, environment_scope: 'review/*')
-      end
-
-      let(:environment) { 'review/name' }
-
-      subject { project.deployment_platform(environment: environment) }
-
-      context 'when environment scope is exactly matched' do
-        before do
-          cluster.update!(environment_scope: 'review/name')
-        end
-
-        it_behaves_like 'matching environment scope'
-      end
-
-      context 'when environment scope is matched by wildcard' do
-        before do
-          cluster.update!(environment_scope: 'review/*')
-        end
-
-        it_behaves_like 'matching environment scope'
-      end
-
-      context 'when environment scope does not match' do
-        before do
-          cluster.update!(environment_scope: 'review/*/special')
-        end
-
-        it_behaves_like 'not matching environment scope'
-      end
-    end
-
-    context 'when environment is specified' do
-      let!(:default_cluster) { create(:cluster, :provided_by_user, projects: [project], environment_scope: '*') }
-      let!(:cluster) { create(:cluster, :provided_by_user, environment_scope: 'review/*', projects: [project]) }
-
-      let!(:group_default_cluster) do
-        create(:cluster, :provided_by_user,
-               cluster_type: :group_type, groups: [group], environment_scope: '*')
-      end
-
-      let(:environment) { 'review/name' }
-
-      subject { project.deployment_platform(environment: environment) }
-
-      context 'when environment scope is exactly matched' do
-        before do
-          cluster.update!(environment_scope: 'review/name')
-        end
-
-        it_behaves_like 'matching environment scope'
-      end
-
-      context 'when environment scope is matched by wildcard' do
-        before do
-          cluster.update!(environment_scope: 'review/*')
-        end
-
-        it_behaves_like 'matching environment scope'
-      end
-
-      context 'when environment scope does not match' do
-        before do
-          cluster.update!(environment_scope: 'review/*/special')
-        end
-
-        it_behaves_like 'not matching environment scope'
-      end
-
-      context 'when environment scope has _' do
-        before do
-          stub_licensed_features(multiple_clusters: true)
-        end
-
-        it 'does not treat it as wildcard' do
-          cluster.update!(environment_scope: 'foo_bar/*')
-
-          is_expected.to eq(default_cluster.platform_kubernetes)
-        end
-
-        context 'when environment name contains an underscore' do
-          let(:environment) { 'foo_bar/test' }
-
-          it 'matches literally for _' do
-            cluster.update!(environment_scope: 'foo_bar/*')
-
-            is_expected.to eq(cluster.platform_kubernetes)
-          end
-        end
-      end
-
-      # The environment name and scope cannot have % at the moment,
-      # but we're considering relaxing it and we should also make sure
-      # it doesn't break in case some data sneaked in somehow as we're
-      # not checking this integrity in database level.
-      context 'when environment scope has %' do
-        before do
-          stub_licensed_features(multiple_clusters: true)
-        end
-
-        it 'does not treat it as wildcard' do
-          cluster.update_attribute(:environment_scope, '*%*')
-
-          is_expected.to eq(default_cluster.platform_kubernetes)
-        end
-
-        context 'when environment name contains a percent char' do
-          let(:environment) { 'foo%bar/test' }
-
-          it 'matches literally for %' do
-            cluster.update_attribute(:environment_scope, 'foo%bar/*')
-
-            is_expected.to eq(cluster.platform_kubernetes)
-          end
-        end
-      end
-
-      context 'when perfectly matched cluster exists' do
-        let!(:perfectly_matched_cluster) { create(:cluster, :provided_by_user, projects: [project], environment_scope: 'review/name') }
-
-        before do
-          stub_licensed_features(multiple_clusters: true)
-        end
-
-        it 'returns perfectly matched cluster as highest precedence' do
-          is_expected.to eq(perfectly_matched_cluster.platform_kubernetes)
-        end
-      end
-    end
-
-    context 'with multiple clusters and multiple environments' do
-      let!(:cluster_1) { create(:cluster, :provided_by_user, projects: [project], environment_scope: 'staging/*') }
-      let!(:cluster_2) { create(:cluster, :provided_by_user, projects: [project], environment_scope: 'test/*') }
-
-      let(:environment_1) { 'staging/name' }
-      let(:environment_2) { 'test/name' }
-
-      before do
-        stub_licensed_features(multiple_clusters: true)
-      end
-
-      it 'returns the appropriate cluster' do
-        expect(project.deployment_platform(environment: environment_1)).to eq(cluster_1.platform_kubernetes)
-        expect(project.deployment_platform(environment: environment_2)).to eq(cluster_2.platform_kubernetes)
-      end
-    end
-  end
-end

ee/spec/models/ee/clusters/cluster_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Clusters::Cluster do
-  it { is_expected.to include_module(HasEnvironmentScope) }
-
-  describe 'validation' do
-    subject { cluster.valid? }
-
-    context 'when validates unique_environment_scope' do
-      context 'for a project cluster' do
-        let(:project) { create(:project) }
-
-        before do
-          create(:cluster, projects: [project], environment_scope: 'product/*')
-        end
-
-        context 'when identical environment scope exists in project' do
-          let(:cluster) { build(:cluster, projects: [project], environment_scope: 'product/*') }
-
-          it { is_expected.to be_falsey }
-        end
-
-        context 'when identical environment scope does not exist in project' do
-          let(:cluster) { build(:cluster, projects: [project], environment_scope: '*') }
-
-          it { is_expected.to be_truthy }
-        end
-
-        context 'when identical environment scope exists in different project' do
-          let(:project2) { create(:project) }
-          let(:cluster) { build(:cluster, projects: [project2], environment_scope: 'product/*') }
-
-          it { is_expected.to be_truthy }
-        end
-      end
-
-      context 'for a group cluster' do
-        let(:group) { create(:group) }
-
-        before do
-          create(:cluster, cluster_type: :group_type, groups: [group], environment_scope: 'product/*')
-        end
-
-        context 'when identical environment scope exists in group' do
-          let(:cluster) { build(:cluster, cluster_type: :group_type, groups: [group], environment_scope: 'product/*') }
-
-          it { is_expected.to be_falsey }
-        end
-
-        context 'when identical environment scope does not exist in group' do
-          let(:cluster) { build(:cluster, cluster_type: :group_type, groups: [group], environment_scope: '*') }
-
-          it { is_expected.to be_truthy }
-        end
-
-        context 'when identical environment scope exists in different group' do
-          let(:cluster) { build(:cluster, :group, environment_scope: 'product/*') }
-
-          it { is_expected.to be_truthy }
-        end
-      end
-
-      context 'for an instance cluster' do
-        before do
-          create(:cluster, :instance, environment_scope: 'product/*')
-        end
-
-        context 'identical environment scope exists' do
-          let(:cluster) { build(:cluster, :instance, environment_scope: 'product/*') }
-
-          it { is_expected.to be_falsey }
-        end
-
-        context 'identical environment scope does not exist' do
-          let(:cluster) { build(:cluster, :instance, environment_scope: '*') }
-
-          it { is_expected.to be_truthy }
-        end
-      end
-    end
-  end
-end

ee/spec/models/project_spec.rb

@@ -442,12 +442,6 @@ RSpec.describe Project do
   end
 
   describe '#deployment_variables' do
-    context 'when project has a deployment platforms' do
-      context 'when multiple clusters (EEP) is enabled' do
-        before do
-          stub_licensed_features(multiple_clusters: true)
-        end
-
     let(:project) { create(:project) }
 
     let!(:default_cluster) do
@@ -489,8 +483,6 @@ RSpec.describe Project do
       end
     end
   end
-    end
-  end
 
   describe '#ensure_external_webhook_token' do
     let(:project) { create(:project, :repository) }

ee/spec/requests/api/group_clusters_spec.rb

@@ -52,25 +52,6 @@ RSpec.describe API::GroupClusters do
         expect(json_response['environment_scope']).to eq('*')
       end
     end
-
-    context 'when license has multiple clusters feature' do
-      before do
-        stub_licensed_features(multiple_clusters: true)
-
-        create(:cluster, :provided_by_gcp, :group,
-               groups: [group])
-
-        post api("/groups/#{group.id}/clusters/user", current_user), params: cluster_params
-      end
-
-      it 'responds with 201' do
-        expect(response).to have_gitlab_http_status(:created)
-      end
-
-      it 'allows multiple clusters to be associated to group' do
-        expect(group.reload.clusters.count).to eq(2)
-      end
-    end
   end
 
   describe 'PUT /groups/:id/clusters/:cluster_id' do

ee/spec/requests/api/project_clusters_spec.rb

@@ -78,10 +78,8 @@ RSpec.describe API::ProjectClusters do
       end
     end
 
-    context 'when license has multiple clusters feature' do
+    context 'when another cluster exists' do
       before do
-        stub_licensed_features(multiple_clusters: true)
-
         create(:cluster, :provided_by_gcp, :project,
                projects: [project])
 

ee/spec/services/ee/clusters/create_service_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Clusters::CreateService do
-  let(:access_token) { 'xxx' }
-  let(:project) { create(:project) }
-  let(:user) { create(:user) }
-  let!(:cluster) { create(:cluster, :provided_by_gcp, :production_environment, projects: [project]) }
-
-  subject { described_class.new(user, params).execute(access_token: access_token) }
-
-  before do
-    allow(project).to receive(:feature_available?).and_call_original
-  end
-
-  context 'when license has multiple clusters feature' do
-    before do
-      allow(project).to receive(:feature_available?).with(:multiple_clusters).and_return(true)
-    end
-
-    context 'when correct params' do
-      let(:params) do
-        {
-          name: 'test-cluster',
-          provider_type: :gcp,
-          provider_gcp_attributes: {
-            gcp_project_id: 'gcp-project',
-            zone: 'us-central1-a',
-            num_nodes: 1,
-            machine_type: 'machine_type-a',
-            legacy_abac: 'true'
-          },
-          clusterable: project
-        }
-      end
-
-      include_examples 'create cluster service success'
-    end
-
-    context 'when invalid params' do
-      let(:params) do
-        {
-          name: 'test-cluster',
-          provider_type: :gcp,
-          provider_gcp_attributes: {
-            gcp_project_id: '!!!!!!!',
-            zone: 'us-central1-a',
-            num_nodes: 1,
-            machine_type: 'machine_type-a'
-          },
-          clusterable: project
-        }
-      end
-
-      include_examples 'create cluster service error'
-    end
-  end
-
-  context 'when license does not have multiple clusters feature' do
-    include_context 'valid cluster create params'
-
-    before do
-      allow(project).to receive(:feature_available?).with(:multiple_clusters).and_return(false)
-    end
-
-    it 'does not create a cluster' do
-      expect(ClusterProvisionWorker).not_to receive(:perform_async)
-      expect { subject }.to raise_error(ArgumentError).and change { Clusters::Cluster.count }.by(0)
-    end
-  end
-end

ee/spec/services/projects/prometheus/alerts/notify_service_spec.rb

@@ -118,8 +118,6 @@ RSpec.describe Projects::Prometheus::Alerts::NotifyService do
       end
 
       before do
-        stub_licensed_features(multiple_clusters: true)
-
         create(:clusters_applications_prometheus, :installed,
                cluster: prd_cluster, alert_manager_token: token)
         create(:clusters_applications_prometheus, :installed,

lib/api/group_clusters.rb

@@ -6,18 +6,6 @@ module API
 
     before { authenticate! }
 
-    # EE::API::GroupClusters will
-    # override these methods
-    helpers do
-      params :create_params_ee do
-      end
-
-      params :update_params_ee do
-      end
-    end
-
-    prepend_if_ee('EE::API::GroupClusters') # rubocop: disable Cop/InjectEnterpriseEditionModule
-
     params do
       requires :id, type: String, desc: 'The ID of the group'
     end
@@ -52,6 +40,7 @@ module API
       params do
         requires :name, type: String, desc: 'Cluster name'
         optional :enabled, type: Boolean, default: true, desc: 'Determines if cluster is active or not, defaults to true'
+        optional :environment_scope, default: '*', type: String, desc: 'The associated environment to the cluster'
         optional :domain, type: String, desc: 'Cluster base domain'
         optional :management_project_id, type: Integer, desc: 'The ID of the management project'
         optional :managed, type: Boolean, default: true, desc: 'Determines if GitLab will manage namespaces and service accounts for this cluster, defaults to true'
@@ -62,7 +51,6 @@ module API
           optional :namespace, type: String, desc: 'Unique namespace related to Group'
           optional :authorization_type, type: String, values: ::Clusters::Platforms::Kubernetes.authorization_types.keys, default: 'rbac', desc: 'Cluster authorization type, defaults to RBAC'
         end
-        use :create_params_ee
       end
       post ':id/clusters/user' do
         authorize! :add_cluster, user_group
@@ -85,6 +73,7 @@ module API
         requires :cluster_id, type: Integer, desc: 'The cluster ID'
         optional :name, type: String, desc: 'Cluster name'
         optional :domain, type: String, desc: 'Cluster base domain'
+        optional :environment_scope, type: String, desc: 'The associated environment to the cluster'
         optional :management_project_id, type: Integer, desc: 'The ID of the management project'
         optional :platform_kubernetes_attributes, type: Hash, desc: %q(Platform Kubernetes data) do
           optional :api_url, type: String, desc: 'URL to access the Kubernetes API'
@@ -92,7 +81,6 @@ module API
           optional :ca_cert, type: String, desc: 'TLS certificate (needed if API is using a self-signed TLS certificate)'
           optional :namespace, type: String, desc: 'Unique namespace related to Group'
         end
-        use :update_params_ee
       end
       put ':id/clusters/:cluster_id' do
         authorize! :update_cluster, cluster

lib/api/project_clusters.rb

@@ -6,18 +6,6 @@ module API
 
     before { authenticate! }
 
-    # EE::API::ProjectClusters will
-    # override these methods
-    helpers do
-      params :create_params_ee do
-      end
-
-      params :update_params_ee do
-      end
-    end
-
-    prepend_if_ee('EE::API::ProjectClusters') # rubocop: disable Cop/InjectEnterpriseEditionModule
-
     params do
       requires :id, type: String, desc: 'The ID of the project'
     end
@@ -56,6 +44,7 @@ module API
         requires :name, type: String, desc: 'Cluster name'
         optional :enabled, type: Boolean, default: true, desc: 'Determines if cluster is active or not, defaults to true'
         optional :domain, type: String, desc: 'Cluster base domain'
+        optional :environment_scope, default: '*', type: String, desc: 'The associated environment to the cluster'
         optional :management_project_id, type: Integer, desc: 'The ID of the management project'
         optional :managed, type: Boolean, default: true, desc: 'Determines if GitLab will manage namespaces and service accounts for this cluster, defaults to true'
         requires :platform_kubernetes_attributes, type: Hash, desc: %q(Platform Kubernetes data) do
@@ -65,7 +54,6 @@ module API
           optional :namespace, type: String, desc: 'Unique namespace related to Project'
           optional :authorization_type, type: String, values: ::Clusters::Platforms::Kubernetes.authorization_types.keys, default: 'rbac', desc: 'Cluster authorization type, defaults to RBAC'
         end
-        use :create_params_ee
       end
       post ':id/clusters/user' do
         authorize! :add_cluster, user_project
@@ -89,6 +77,7 @@ module API
         requires :cluster_id, type: Integer, desc: 'The cluster ID'
         optional :name, type: String, desc: 'Cluster name'
         optional :domain, type: String, desc: 'Cluster base domain'
+        optional :environment_scope, type: String, desc: 'The associated environment to the cluster'
         optional :management_project_id, type: Integer, desc: 'The ID of the management project'
         optional :platform_kubernetes_attributes, type: Hash, desc: %q(Platform Kubernetes data) do
           optional :api_url, type: String, desc: 'URL to access the Kubernetes API'
@@ -96,7 +85,6 @@ module API
           optional :ca_cert, type: String, desc: 'TLS certificate (needed if API is using a self-signed TLS certificate)'
           optional :namespace, type: String, desc: 'Unique namespace related to Project'
         end
-        use :update_params_ee
       end
       put ':id/clusters/:cluster_id' do
         authorize! :update_cluster, cluster

locale/gitlab.pot

@@ -12490,9 +12490,6 @@ msgstr ""
 msgid "Instance administrators group already exists"
 msgstr ""
 
-msgid "Instance does not support multiple Kubernetes clusters"
-msgstr ""
-
 msgid "Instance license"
 msgstr ""
 

spec/features/projects/clusters/gcp_spec.rb

@@ -139,6 +139,19 @@ RSpec.describe 'Gcp Cluster', :js, :do_not_mock_admin_mode do
         end
       end
 
+      context 'when a user adds an existing cluster' do
+        before do
+          visit project_clusters_path(project)
+
+          click_link 'Add Kubernetes cluster'
+          click_link 'Add existing cluster'
+        end
+
+        it 'user sees the "Environment scope" field' do
+          expect(page).to have_css('#cluster_environment_scope')
+        end
+      end
+
       context 'when user destroys the cluster' do
         before do
           click_link 'Advanced Settings'
@@ -155,19 +168,6 @@ RSpec.describe 'Gcp Cluster', :js, :do_not_mock_admin_mode do
     end
   end
 
-  context 'when a user cannot edit the environment scope' do
-    before do
-      visit project_clusters_path(project)
-
-      click_link 'Add Kubernetes cluster'
-      click_link 'Add existing cluster'
-    end
-
-    it 'user does not see the "Environment scope" field' do
-      expect(page).not_to have_css('#cluster_environment_scope')
-    end
-  end
-
   context 'when user has not dismissed GCP signup offer' do
     before do
       visit project_clusters_path(project)

spec/features/projects/clusters_spec.rb

@@ -25,6 +25,168 @@ RSpec.describe 'Clusters', :js do
     end
   end
 
+  context 'when user has a cluster' do
+    before do
+      allow_any_instance_of(Clusters::Cluster).to receive(:retrieve_connection_status).and_return(:connected)
+    end
+
+    context 'when user adds an existing cluster' do
+      before do
+        create(:cluster, :provided_by_user, name: 'default-cluster', environment_scope: '*', projects: [project])
+        visit project_clusters_path(project)
+      end
+
+      it 'user sees an add cluster button' do
+        expect(page).to have_selector('.js-add-cluster:not(.readonly)')
+      end
+
+      context 'when user filled form with environment scope' do
+        before do
+          click_link 'Add Kubernetes cluster'
+          click_link 'Add existing cluster'
+          fill_in 'cluster_name', with: 'staging-cluster'
+          fill_in 'cluster_environment_scope', with: 'staging/*'
+          click_button 'Add Kubernetes cluster'
+        end
+
+        it 'user sees a cluster details page' do
+          expect(page.find_field('cluster[name]').value).to eq('staging-cluster')
+          expect(page.find_field('cluster[environment_scope]').value).to eq('staging/*')
+        end
+      end
+
+      context 'when user updates environment scope' do
+        before do
+          click_link 'default-cluster'
+          fill_in 'cluster_environment_scope', with: 'production/*'
+          within '.js-cluster-integration-form' do
+            click_button 'Save changes'
+          end
+        end
+
+        it 'updates the environment scope' do
+          expect(page.find_field('cluster[environment_scope]').value).to eq('production/*')
+        end
+      end
+
+      context 'when user updates duplicated environment scope' do
+        before do
+          click_link 'Add Kubernetes cluster'
+          click_link 'Add existing cluster'
+          fill_in 'cluster_name', with: 'staging-cluster'
+          fill_in 'cluster_environment_scope', with: '*'
+          fill_in 'cluster_platform_kubernetes_attributes_api_url', with: 'https://0.0.0.0'
+          fill_in 'cluster_platform_kubernetes_attributes_token', with: 'token'
+
+          click_button 'Add Kubernetes cluster'
+        end
+
+        it 'users sees an environment scope validation error' do
+          expect(page).to have_content('cannot add duplicated environment scope')
+        end
+      end
+    end
+
+    context 'when user adds a Google Kubernetes Engine cluster' do
+      before do
+        allow_any_instance_of(Projects::ClustersController)
+          .to receive(:token_in_session).and_return('token')
+        allow_any_instance_of(Projects::ClustersController)
+          .to receive(:expires_at_in_session).and_return(1.hour.since.to_i.to_s)
+
+        allow_any_instance_of(Projects::ClustersController).to receive(:authorize_google_project_billing)
+        allow_any_instance_of(Projects::ClustersController).to receive(:google_project_billing_status).and_return(true)
+
+        allow_any_instance_of(GoogleApi::CloudPlatform::Client)
+          .to receive(:projects_zones_clusters_create) do
+          OpenStruct.new(
+            self_link: 'projects/gcp-project-12345/zones/us-central1-a/operations/ope-123',
+            status: 'RUNNING'
+          )
+        end
+
+        allow(WaitForClusterCreationWorker).to receive(:perform_in).and_return(nil)
+
+        create(:cluster, :provided_by_gcp, name: 'default-cluster', environment_scope: '*', projects: [project])
+        visit project_clusters_path(project)
+      end
+
+      it 'user sees a add cluster button ' do
+        expect(page).to have_selector('.js-add-cluster:not(.readonly)')
+      end
+
+      context 'when user filled form with environment scope' do
+        before do
+          click_link 'Add Kubernetes cluster'
+          click_link 'Create new cluster'
+          click_link 'Google GKE'
+
+          sleep 2 # wait for ajax
+          execute_script('document.querySelector(".js-gcp-project-id-dropdown input").setAttribute("type", "text")')
+          execute_script('document.querySelector(".js-gcp-zone-dropdown input").setAttribute("type", "text")')
+          execute_script('document.querySelector(".js-gcp-machine-type-dropdown input").setAttribute("type", "text")')
+          execute_script('document.querySelector(".js-gke-cluster-creation-submit").removeAttribute("disabled")')
+
+          fill_in 'cluster_name', with: 'staging-cluster'
+          fill_in 'cluster_environment_scope', with: 'staging/*'
+          fill_in 'cluster[provider_gcp_attributes][gcp_project_id]', with: 'gcp-project-123'
+          fill_in 'cluster[provider_gcp_attributes][zone]', with: 'us-central1-a'
+          fill_in 'cluster[provider_gcp_attributes][machine_type]', with: 'n1-standard-2'
+          click_button 'Create Kubernetes cluster'
+
+          # The frontend won't show the details until the cluster is
+          # created, and we don't want to make calls out to GCP.
+          provider = Clusters::Cluster.last.provider
+          provider.make_created
+        end
+
+        it 'user sees a cluster details page' do
+          expect(page).to have_content('GitLab Integration')
+          expect(page.find_field('cluster[environment_scope]').value).to eq('staging/*')
+        end
+      end
+
+      context 'when user updates environment scope' do
+        before do
+          click_link 'default-cluster'
+          fill_in 'cluster_environment_scope', with: 'production/*'
+          within ".js-cluster-integration-form" do
+            click_button 'Save changes'
+          end
+        end
+
+        it 'updates the environment scope' do
+          expect(page.find_field('cluster[environment_scope]').value).to eq('production/*')
+        end
+      end
+
+      context 'when user updates duplicated environment scope' do
+        before do
+          click_link 'Add Kubernetes cluster'
+          click_link 'Create new cluster'
+          click_link 'Google GKE'
+
+          sleep 2 # wait for ajax
+          execute_script('document.querySelector(".js-gcp-project-id-dropdown input").setAttribute("type", "text")')
+          execute_script('document.querySelector(".js-gcp-zone-dropdown input").setAttribute("type", "text")')
+          execute_script('document.querySelector(".js-gcp-machine-type-dropdown input").setAttribute("type", "text")')
+          execute_script('document.querySelector(".js-gke-cluster-creation-submit").removeAttribute("disabled")')
+
+          fill_in 'cluster_name', with: 'staging-cluster'
+          fill_in 'cluster_environment_scope', with: '*'
+          fill_in 'cluster[provider_gcp_attributes][gcp_project_id]', with: 'gcp-project-123'
+          fill_in 'cluster[provider_gcp_attributes][zone]', with: 'us-central1-a'
+          fill_in 'cluster[provider_gcp_attributes][machine_type]', with: 'n1-standard-2'
+          click_button 'Create Kubernetes cluster'
+        end
+
+        it 'users sees an environment scope validation error' do
+          expect(page).to have_content('cannot add duplicated environment scope')
+        end
+      end
+    end
+  end
+
   context 'when user has a cluster and visits cluster index page' do
     let!(:cluster) { create(:cluster, :project, :provided_by_gcp) }
     let(:project) { cluster.project }

spec/helpers/clusters_helper_spec.rb

@@ -101,6 +101,12 @@ RSpec.describe ClustersHelper do
     end
   end
 
+  describe '#has_multiple_clusters?' do
+    subject { helper.has_multiple_clusters? }
+
+    it { is_expected.to be_truthy }
+  end
+
   describe '#cluster_type_label' do
     subject { helper.cluster_type_label(cluster_type) }
 

spec/models/clusters/cluster_spec.rb

@@ -10,6 +10,7 @@ RSpec.describe Clusters::Cluster, :use_clean_rails_memory_store_caching do
 
   subject { build(:cluster) }
 
+  it { is_expected.to include_module(HasEnvironmentScope) }
   it { is_expected.to belong_to(:user) }
   it { is_expected.to belong_to(:management_project).class_name('::Project') }
   it { is_expected.to have_many(:cluster_projects) }
@@ -289,6 +290,79 @@ RSpec.describe Clusters::Cluster, :use_clean_rails_memory_store_caching do
   describe 'validations' do
     subject { cluster.valid? }
 
+    context 'when validates unique_environment_scope' do
+      context 'for a project cluster' do
+        let(:project) { create(:project) }
+
+        before do
+          create(:cluster, projects: [project], environment_scope: 'product/*')
+        end
+
+        context 'when identical environment scope exists in project' do
+          let(:cluster) { build(:cluster, projects: [project], environment_scope: 'product/*') }
+
+          it { is_expected.to be_falsey }
+        end
+
+        context 'when identical environment scope does not exist in project' do
+          let(:cluster) { build(:cluster, projects: [project], environment_scope: '*') }
+
+          it { is_expected.to be_truthy }
+        end
+
+        context 'when identical environment scope exists in different project' do
+          let(:project2) { create(:project) }
+          let(:cluster) { build(:cluster, projects: [project2], environment_scope: 'product/*') }
+
+          it { is_expected.to be_truthy }
+        end
+      end
+
+      context 'for a group cluster' do
+        let(:group) { create(:group) }
+
+        before do
+          create(:cluster, cluster_type: :group_type, groups: [group], environment_scope: 'product/*')
+        end
+
+        context 'when identical environment scope exists in group' do
+          let(:cluster) { build(:cluster, cluster_type: :group_type, groups: [group], environment_scope: 'product/*') }
+
+          it { is_expected.to be_falsey }
+        end
+
+        context 'when identical environment scope does not exist in group' do
+          let(:cluster) { build(:cluster, cluster_type: :group_type, groups: [group], environment_scope: '*') }
+
+          it { is_expected.to be_truthy }
+        end
+
+        context 'when identical environment scope exists in different group' do
+          let(:cluster) { build(:cluster, :group, environment_scope: 'product/*') }
+
+          it { is_expected.to be_truthy }
+        end
+      end
+
+      context 'for an instance cluster' do
+        before do
+          create(:cluster, :instance, environment_scope: 'product/*')
+        end
+
+        context 'identical environment scope exists' do
+          let(:cluster) { build(:cluster, :instance, environment_scope: 'product/*') }
+
+          it { is_expected.to be_falsey }
+        end
+
+        context 'identical environment scope does not exist' do
+          let(:cluster) { build(:cluster, :instance, environment_scope: '*') }
+
+          it { is_expected.to be_truthy }
+        end
+      end
+    end
+
     context 'when validates name' do
       context 'when provided by user' do
         let!(:cluster) { build(:cluster, :provided_by_user, name: name) }

spec/models/concerns/deployment_platform_spec.rb

@@ -8,6 +8,241 @@ RSpec.describe DeploymentPlatform do
   describe '#deployment_platform' do
     subject { project.deployment_platform }
 
+    context 'multiple clusters' do
+      let(:group) { create(:group) }
+      let(:project) { create(:project, group: group) }
+
+      shared_examples 'matching environment scope' do
+        it 'returns environment specific cluster' do
+          is_expected.to eq(cluster.platform_kubernetes)
+        end
+      end
+
+      shared_examples 'not matching environment scope' do
+        it 'returns default cluster' do
+          is_expected.to eq(default_cluster.platform_kubernetes)
+        end
+      end
+
+      context 'multiple clusters use the same management project' do
+        let(:management_project) { create(:project, group: group) }
+
+        let!(:default_cluster) do
+          create(:cluster_for_group, groups: [group], environment_scope: '*', management_project: management_project)
+        end
+
+        let!(:cluster) do
+          create(:cluster_for_group, groups: [group], environment_scope: 'review/*', management_project: management_project)
+        end
+
+        let(:environment) { 'review/name' }
+
+        subject { management_project.deployment_platform(environment: environment) }
+
+        it_behaves_like 'matching environment scope'
+      end
+
+      context 'when project does not have a cluster but has group clusters' do
+        let!(:default_cluster) do
+          create(:cluster, :provided_by_user,
+                cluster_type: :group_type, groups: [group], environment_scope: '*')
+        end
+
+        let!(:cluster) do
+          create(:cluster, :provided_by_user,
+                cluster_type: :group_type, environment_scope: 'review/*', groups: [group])
+        end
+
+        let(:environment) { 'review/name' }
+
+        subject { project.deployment_platform(environment: environment) }
+
+        context 'when environment scope is exactly matched' do
+          before do
+            cluster.update!(environment_scope: 'review/name')
+          end
+
+          it_behaves_like 'matching environment scope'
+        end
+
+        context 'when environment scope is matched by wildcard' do
+          before do
+            cluster.update!(environment_scope: 'review/*')
+          end
+
+          it_behaves_like 'matching environment scope'
+        end
+
+        context 'when environment scope does not match' do
+          before do
+            cluster.update!(environment_scope: 'review/*/special')
+          end
+
+          it_behaves_like 'not matching environment scope'
+        end
+
+        context 'when group belongs to a parent group' do
+          let(:parent_group) { create(:group) }
+          let(:group) { create(:group, parent: parent_group) }
+
+          context 'when parent_group has a cluster with default scope' do
+            let!(:parent_group_cluster) do
+              create(:cluster, :provided_by_user,
+                    cluster_type: :group_type, environment_scope: '*', groups: [parent_group])
+            end
+
+            it_behaves_like 'matching environment scope'
+          end
+
+          context 'when parent_group has a cluster that is an exact match' do
+            let!(:parent_group_cluster) do
+              create(:cluster, :provided_by_user,
+                    cluster_type: :group_type, environment_scope: 'review/name', groups: [parent_group])
+            end
+
+            it_behaves_like 'matching environment scope'
+          end
+        end
+      end
+
+      context 'with instance clusters' do
+        let!(:default_cluster) do
+          create(:cluster, :provided_by_user, :instance, environment_scope: '*')
+        end
+
+        let!(:cluster) do
+          create(:cluster, :provided_by_user, :instance, environment_scope: 'review/*')
+        end
+
+        let(:environment) { 'review/name' }
+
+        subject { project.deployment_platform(environment: environment) }
+
+        context 'when environment scope is exactly matched' do
+          before do
+            cluster.update!(environment_scope: 'review/name')
+          end
+
+          it_behaves_like 'matching environment scope'
+        end
+
+        context 'when environment scope is matched by wildcard' do
+          before do
+            cluster.update!(environment_scope: 'review/*')
+          end
+
+          it_behaves_like 'matching environment scope'
+        end
+
+        context 'when environment scope does not match' do
+          before do
+            cluster.update!(environment_scope: 'review/*/special')
+          end
+
+          it_behaves_like 'not matching environment scope'
+        end
+      end
+
+      context 'when environment is specified' do
+        let!(:default_cluster) { create(:cluster, :provided_by_user, projects: [project], environment_scope: '*') }
+        let!(:cluster) { create(:cluster, :provided_by_user, environment_scope: 'review/*', projects: [project]) }
+
+        let!(:group_default_cluster) do
+          create(:cluster, :provided_by_user,
+                cluster_type: :group_type, groups: [group], environment_scope: '*')
+        end
+
+        let(:environment) { 'review/name' }
+
+        subject { project.deployment_platform(environment: environment) }
+
+        context 'when environment scope is exactly matched' do
+          before do
+            cluster.update!(environment_scope: 'review/name')
+          end
+
+          it_behaves_like 'matching environment scope'
+        end
+
+        context 'when environment scope is matched by wildcard' do
+          before do
+            cluster.update!(environment_scope: 'review/*')
+          end
+
+          it_behaves_like 'matching environment scope'
+        end
+
+        context 'when environment scope does not match' do
+          before do
+            cluster.update!(environment_scope: 'review/*/special')
+          end
+
+          it_behaves_like 'not matching environment scope'
+        end
+
+        context 'when environment scope has _' do
+          it 'does not treat it as wildcard' do
+            cluster.update!(environment_scope: 'foo_bar/*')
+
+            is_expected.to eq(default_cluster.platform_kubernetes)
+          end
+
+          context 'when environment name contains an underscore' do
+            let(:environment) { 'foo_bar/test' }
+
+            it 'matches literally for _' do
+              cluster.update!(environment_scope: 'foo_bar/*')
+
+              is_expected.to eq(cluster.platform_kubernetes)
+            end
+          end
+        end
+
+        # The environment name and scope cannot have % at the moment,
+        # but we're considering relaxing it and we should also make sure
+        # it doesn't break in case some data sneaked in somehow as we're
+        # not checking this integrity in database level.
+        context 'when environment scope has %' do
+          it 'does not treat it as wildcard' do
+            cluster.update_attribute(:environment_scope, '*%*')
+
+            is_expected.to eq(default_cluster.platform_kubernetes)
+          end
+
+          context 'when environment name contains a percent char' do
+            let(:environment) { 'foo%bar/test' }
+
+            it 'matches literally for %' do
+              cluster.update_attribute(:environment_scope, 'foo%bar/*')
+
+              is_expected.to eq(cluster.platform_kubernetes)
+            end
+          end
+        end
+
+        context 'when perfectly matched cluster exists' do
+          let!(:perfectly_matched_cluster) { create(:cluster, :provided_by_user, projects: [project], environment_scope: 'review/name') }
+
+          it 'returns perfectly matched cluster as highest precedence' do
+            is_expected.to eq(perfectly_matched_cluster.platform_kubernetes)
+          end
+        end
+      end
+
+      context 'with multiple clusters and multiple environments' do
+        let!(:cluster_1) { create(:cluster, :provided_by_user, projects: [project], environment_scope: 'staging/*') }
+        let!(:cluster_2) { create(:cluster, :provided_by_user, projects: [project], environment_scope: 'test/*') }
+
+        let(:environment_1) { 'staging/name' }
+        let(:environment_2) { 'test/name' }
+
+        it 'returns the appropriate cluster' do
+          expect(project.deployment_platform(environment: environment_1)).to eq(cluster_1.platform_kubernetes)
+          expect(project.deployment_platform(environment: environment_2)).to eq(cluster_2.platform_kubernetes)
+        end
+      end
+    end
+
     context 'with no Kubernetes configuration on CI/CD, no Kubernetes Service' do
       it { is_expected.to be_nil }
     end

spec/models/project_spec.rb

@@ -2905,17 +2905,12 @@ RSpec.describe Project do
 
     subject { project.deployment_variables(environment: environment, kubernetes_namespace: namespace) }
 
+    context 'when the deployment platform is stubbed' do
       before do
         expect(project).to receive(:deployment_platform).with(environment: environment)
           .and_return(deployment_platform)
       end
 
-    context 'when project has no deployment platform' do
-      let(:deployment_platform) { nil }
-
-      it { is_expected.to eq [] }
-    end
-
       context 'when project has a deployment platform' do
         let(:platform_variables) { %w(platform variables) }
         let(:deployment_platform) { double }
@@ -2928,6 +2923,56 @@ RSpec.describe Project do
 
         it { is_expected.to eq platform_variables }
       end
+
+      context 'when project has no deployment platform' do
+        let(:deployment_platform) { nil }
+
+        it { is_expected.to eq [] }
+      end
+    end
+
+    context 'when project has a deployment platforms' do
+      let(:project) { create(:project) }
+
+      let!(:default_cluster) do
+        create(:cluster,
+                :not_managed,
+                platform_type: :kubernetes,
+                projects: [project],
+                environment_scope: '*',
+                platform_kubernetes: default_cluster_kubernetes)
+      end
+
+      let!(:review_env_cluster) do
+        create(:cluster,
+                :not_managed,
+                platform_type: :kubernetes,
+                projects: [project],
+                environment_scope: 'review/*',
+                platform_kubernetes: review_env_cluster_kubernetes)
+      end
+
+      let(:default_cluster_kubernetes) { create(:cluster_platform_kubernetes, token: 'default-AAA') }
+      let(:review_env_cluster_kubernetes) { create(:cluster_platform_kubernetes, token: 'review-AAA') }
+
+      context 'when environment name is review/name' do
+        let!(:environment) { create(:environment, project: project, name: 'review/name') }
+
+        it 'returns variables from this service' do
+          expect(project.deployment_variables(environment: 'review/name'))
+            .to include(key: 'KUBE_TOKEN', value: 'review-AAA', public: false, masked: true)
+        end
+      end
+
+      context 'when environment name is other' do
+        let!(:environment) { create(:environment, project: project, name: 'staging/name') }
+
+        it 'returns variables from this service' do
+          expect(project.deployment_variables(environment: 'staging/name'))
+            .to include(key: 'KUBE_TOKEN', value: 'default-AAA', public: false, masked: true)
+        end
+      end
+    end
   end
 
   describe '#default_environment' do

spec/requests/api/group_clusters_spec.rb

@@ -266,29 +266,51 @@ RSpec.describe API::GroupClusters do
       end
     end
 
-    context 'when user tries to add multiple clusters' do
+    context 'non-authorized user' do
       before do
-        create(:cluster, :provided_by_gcp, :group,
-               groups: [group])
+        post api("/groups/#{group.id}/clusters/user", developer_user), params: cluster_params
+      end
 
-        post api("/groups/#{group.id}/clusters/user", current_user), params: cluster_params
+      it 'responds with 403' do
+        expect(response).to have_gitlab_http_status(:forbidden)
+
+        expect(json_response['message']).to eq('403 Forbidden')
+      end
+    end
   end
 
-      it 'responds with 400' do
-        expect(response).to have_gitlab_http_status(:bad_request)
-        expect(json_response['message']['base'].first).to eq(_('Instance does not support multiple Kubernetes clusters'))
+  describe 'PUT /groups/:id/clusters/:cluster_id' do
+    let(:api_url) { 'https://kubernetes.example.com' }
+
+    let(:platform_kubernetes_attributes) do
+      {
+        api_url: api_url,
+        token: 'sample-token'
+      }
     end
+
+    let(:cluster_params) do
+      {
+        name: 'test-cluster',
+        environment_scope: 'test/*',
+        platform_kubernetes_attributes: platform_kubernetes_attributes
+      }
     end
 
-    context 'non-authorized user' do
+    context 'when another cluster exists' do
       before do
-        post api("/groups/#{group.id}/clusters/user", developer_user), params: cluster_params
+        create(:cluster, :provided_by_gcp, :group,
+               groups: [group])
+
+        post api("/groups/#{group.id}/clusters/user", current_user), params: cluster_params
       end
 
-      it 'responds with 403' do
-        expect(response).to have_gitlab_http_status(:forbidden)
+      it 'responds with 201' do
+        expect(response).to have_gitlab_http_status(:created)
+      end
 
-        expect(json_response['message']).to eq('403 Forbidden')
+      it 'allows multiple clusters to be associated to group' do
+        expect(group.reload.clusters.count).to eq(2)
       end
     end
   end

spec/requests/api/project_clusters_spec.rb

@@ -40,7 +40,7 @@ RSpec.describe API::ProjectClusters do
         expect(response).to include_pagination_headers
       end
 
-      it 'onlies include authorized clusters' do
+      it 'only includes authorized clusters' do
         cluster_ids = json_response.map { |cluster| cluster['id'] }
 
         expect(response).to have_gitlab_http_status(:ok)
@@ -258,29 +258,52 @@ RSpec.describe API::ProjectClusters do
       end
     end
 
-    context 'when user tries to add multiple clusters' do
+    context 'non-authorized user' do
       before do
-        create(:cluster, :provided_by_gcp, :project,
-               projects: [project])
+        post api("/projects/#{project.id}/clusters/user", developer_user), params: cluster_params
+      end
 
-        post api("/projects/#{project.id}/clusters/user", current_user), params: cluster_params
+      it 'responds with 403' do
+        expect(response).to have_gitlab_http_status(:forbidden)
+        expect(json_response['message']).to eq('403 Forbidden')
+      end
+    end
   end
 
-      it 'responds with 400' do
-        expect(response).to have_gitlab_http_status(:bad_request)
-        expect(json_response['message']['base'].first)
-          .to eq(_('Instance does not support multiple Kubernetes clusters'))
+  describe 'POST /projects/:id/clusters/user with multiple clusters' do
+    let(:api_url) { 'https://kubernetes.example.com' }
+    let(:namespace) { project.path }
+
+    let(:platform_kubernetes_attributes) do
+      {
+        api_url: api_url,
+        token: 'sample-token',
+        namespace: namespace
+      }
     end
+
+    let(:cluster_params) do
+      {
+        name: 'test-cluster',
+        environment_scope: 'production/*',
+        platform_kubernetes_attributes: platform_kubernetes_attributes
+      }
     end
 
-    context 'non-authorized user' do
+    context 'when another cluster exists' do
       before do
-        post api("/projects/#{project.id}/clusters/user", developer_user), params: cluster_params
+        create(:cluster, :provided_by_gcp, :project,
+               projects: [project])
+
+        post api("/projects/#{project.id}/clusters/user", current_user), params: cluster_params
       end
 
-      it 'responds with 403' do
-        expect(response).to have_gitlab_http_status(:forbidden)
-        expect(json_response['message']).to eq('403 Forbidden')
+      it 'responds with 201' do
+        expect(response).to have_gitlab_http_status(:created)
+      end
+
+      it 'allows multiple clusters to be associated to project' do
+        expect(project.reload.clusters.count).to eq(2)
       end
     end
   end

spec/services/clusters/create_service_spec.rb

@@ -53,13 +53,54 @@ RSpec.describe Clusters::CreateService do
       include_context 'valid cluster create params'
       let!(:cluster) { create(:cluster, :provided_by_gcp, :production_environment, projects: [project]) }
 
-      it 'does not create a cluster' do
-        expect(ClusterProvisionWorker).not_to receive(:perform_async)
-        expect { subject }.to raise_error(ArgumentError).and change { Clusters::Cluster.count }.by(0)
+      it 'creates another cluster' do
+        expect(ClusterProvisionWorker).to receive(:perform_async)
+        expect { subject }.to change { Clusters::Cluster.count }.by(1)
       end
     end
   end
 
+  context 'when another cluster exists' do
+    let!(:cluster) { create(:cluster, :provided_by_gcp, :production_environment, projects: [project]) }
+
+    context 'when correct params' do
+      let(:params) do
+        {
+          name: 'test-cluster',
+          provider_type: :gcp,
+          provider_gcp_attributes: {
+            gcp_project_id: 'gcp-project',
+            zone: 'us-central1-a',
+            num_nodes: 1,
+            machine_type: 'machine_type-a',
+            legacy_abac: 'true'
+          },
+          clusterable: project
+        }
+      end
+
+      include_examples 'create cluster service success'
+    end
+
+    context 'when invalid params' do
+      let(:params) do
+        {
+          name: 'test-cluster',
+          provider_type: :gcp,
+          provider_gcp_attributes: {
+            gcp_project_id: '!!!!!!!',
+            zone: 'us-central1-a',
+            num_nodes: 1,
+            machine_type: 'machine_type-a'
+          },
+          clusterable: project
+        }
+      end
+
+      include_examples 'create cluster service error'
+    end
+  end
+
   context 'when params includes :management_project_id' do
     subject(:cluster) { described_class.new(user, params).execute(access_token: access_token) }
 

spec/services/projects/prometheus/alerts/notify_service_spec.rb

@@ -102,6 +102,41 @@ RSpec.describe Projects::Prometheus::Alerts::NotifyService do
     let(:payload_alert_firing) { payload_raw['alerts'].first }
     let(:token) { 'token' }
 
+    context 'with environment specific clusters' do
+      let(:prd_cluster) do
+        cluster
+      end
+
+      let(:stg_cluster) do
+        create(:cluster, :provided_by_user, projects: [project], enabled: true, environment_scope: 'stg/*')
+      end
+
+      let(:stg_environment) do
+        create(:environment, project: project, name: 'stg/1')
+      end
+
+      let(:alert_firing) do
+        create(:prometheus_alert, project: project, environment: stg_environment)
+      end
+
+      before do
+        create(:clusters_applications_prometheus, :installed,
+               cluster: prd_cluster, alert_manager_token: token)
+        create(:clusters_applications_prometheus, :installed,
+               cluster: stg_cluster, alert_manager_token: nil)
+      end
+
+      context 'without token' do
+        let(:token_input) { nil }
+
+        it_behaves_like 'notifies alerts'
+      end
+
+      context 'with token' do
+        it_behaves_like 'no notifications', http_status: :unauthorized
+      end
+    end
+
     context 'with project specific cluster' do
       using RSpec::Parameterized::TableSyntax
 

spec/support/services/clusters/create_service_shared.rb

 # frozen_string_literal: true
 
 RSpec.shared_context 'valid cluster create params' do
+  let(:clusterable) { Clusters::Instance.new }
   let(:params) do
     {
       name: 'test-cluster',
@@ -11,12 +12,14 @@ RSpec.shared_context 'valid cluster create params' do
         num_nodes: 1,
         machine_type: 'machine_type-a',
         legacy_abac: 'true'
-      }
+      },
+      clusterable: clusterable
     }
   end
 end
 
 RSpec.shared_context 'invalid cluster create params' do
+  let(:clusterable) { Clusters::Instance.new }
   let(:params) do
     {
       name: 'test-cluster',
@@ -26,7 +29,9 @@ RSpec.shared_context 'invalid cluster create params' do
         zone: 'us-central1-a',
         num_nodes: 1,
         machine_type: 'machine_type-a'
-      }
+      },
+      clusterable: clusterable
+
     }
   end
 end