Remove instance_clusters feature_flag

Now we have terminals for instance and group clusters we can remove the
FF now. Deploying to instance clusters has been working without
complaints too.

app/models/clusters/instance.rb

@@ -9,9 +9,5 @@ module Clusters
     def feature_available?(feature)
       ::Feature.enabled?(feature, default_enabled: true)
     end
-
-    def self.enabled?
-      ::Feature.enabled?(:instance_clusters, default_enabled: true)
-    end
   end
 end

app/models/concerns/deployment_platform.rb

@@ -14,7 +14,7 @@ module DeploymentPlatform
   def find_deployment_platform(environment)
     find_cluster_platform_kubernetes(environment: environment) ||
       find_group_cluster_platform_kubernetes(environment: environment) ||
-      find_instance_cluster_platform_kubernetes_with_feature_guard(environment: environment)
+      find_instance_cluster_platform_kubernetes(environment: environment)
   end
 
   # EE would override this and utilize environment argument
@@ -29,12 +29,6 @@ module DeploymentPlatform
       .first&.platform_kubernetes
   end
 
-  def find_instance_cluster_platform_kubernetes_with_feature_guard(environment: nil)
-    return unless Clusters::Instance.enabled?
-
-    find_instance_cluster_platform_kubernetes(environment: environment)
-  end
-
   # EE would override this and utilize environment argument
   def find_instance_cluster_platform_kubernetes(environment: nil)
     Clusters::Instance.new.clusters.enabled.default_environment

app/policies/clusters/instance_policy.rb

@@ -6,9 +6,8 @@ module Clusters
 
     condition(:has_clusters, scope: :subject) { clusterable_has_clusters? }
     condition(:can_have_multiple_clusters) { multiple_clusters_available? }
-    condition(:instance_clusters_enabled) { Instance.enabled? }
 
-    rule { admin & instance_clusters_enabled }.policy do
+    rule { admin }.policy do
       enable :read_cluster
       enable :add_cluster
       enable :create_cluster

changelogs/unreleased/remove_group_and_instance_clusters_feature_flag.yml

+---
+title: Remove group and instance clusters feature flag
+merge_request: 30124
+author:
+type: changed

spec/controllers/admin/clusters/applications_controller_spec.rb

@@ -13,16 +13,6 @@ describe Admin::Clusters::ApplicationsController do
     it { expect { subject }.to be_allowed_for(:admin) }
     it { expect { subject }.to be_denied_for(:user) }
     it { expect { subject }.to be_denied_for(:external) }
-
-    context 'when instance clusters are disabled' do
-      before do
-        stub_feature_flags(instance_clusters: false)
-      end
-
-      it 'returns 404' do
-        is_expected.to have_http_status(:not_found)
-      end
-    end
   end
 
   let(:cluster) { create(:cluster, :instance, :provided_by_gcp) }

spec/controllers/admin/clusters_controller_spec.rb

@@ -17,23 +17,6 @@ describe Admin::ClustersController do
       get :index, params: params
     end
 
-    context 'when feature flag is not enabled' do
-      before do
-        stub_feature_flags(instance_clusters: false)
-      end
-
-      it 'responds with not found' do
-        get_index
-
-        expect(response).to have_gitlab_http_status(404)
-      end
-    end
-
-    context 'when feature flag is enabled' do
-      before do
-        stub_feature_flags(instance_clusters: true)
-      end
-
     describe 'functionality' do
       context 'when instance has one or more clusters' do
         let!(:enabled_cluster) do
@@ -79,7 +62,6 @@ describe Admin::ClustersController do
         end
       end
     end
-    end
 
     describe 'security' do
       let(:cluster) { create(:cluster, :provided_by_gcp, :instance) }

spec/policies/clusters/instance_policy_spec.rb

@@ -16,21 +16,9 @@ describe Clusters::InstancePolicy do
     context 'when admin' do
       let(:user) { create(:admin) }
 
-      context 'with instance_level_clusters enabled' do
       it { expect(policy).to be_allowed :read_cluster }
       it { expect(policy).to be_allowed :update_cluster }
       it { expect(policy).to be_allowed :admin_cluster }
     end
-
-      context 'with instance_level_clusters disabled' do
-        before do
-          stub_feature_flags(instance_clusters: false)
-        end
-
-        it { expect(policy).to be_disallowed :read_cluster }
-        it { expect(policy).to be_disallowed :update_cluster }
-        it { expect(policy).to be_disallowed :admin_cluster }
-      end
-    end
   end
 end