diff --git a/app/controllers/admin/services_controller.rb b/app/controllers/admin/services_controller.rb
index 37a1a23178e..4c3d336b3af 100644
--- a/app/controllers/admin/services_controller.rb
+++ b/app/controllers/admin/services_controller.rb
@@ -16,6 +16,8 @@ class Admin::ServicesController < Admin::ApplicationController
 
   def update
     if service.update_attributes(service_params[:service])
+      PropagateServiceTemplateWorker.perform_async(service.id) if service.active?
+
       redirect_to admin_application_settings_services_path,
         notice: 'Application settings saved successfully'
     else
diff --git a/app/services/projects/propagate_service_template.rb b/app/services/projects/propagate_service_template.rb
new file mode 100644
index 00000000000..a8ef2108492
--- /dev/null
+++ b/app/services/projects/propagate_service_template.rb
@@ -0,0 +1,103 @@
+module Projects
+  class PropagateServiceTemplate
+    BATCH_SIZE = 100
+
+    def self.propagate(*args)
+      new(*args).propagate
+    end
+
+    def initialize(template)
+      @template = template
+    end
+
+    def propagate
+      return unless @template.active?
+
+      Rails.logger.info("Propagating services for template #{@template.id}")
+
+      propagate_projects_with_template
+    end
+
+    private
+
+    def propagate_projects_with_template
+      loop do
+        batch = project_ids_batch
+
+        bulk_create_from_template(batch) unless batch.empty?
+
+        break if batch.size < BATCH_SIZE
+      end
+    end
+
+    def bulk_create_from_template(batch)
+      service_list = batch.map do |project_id|
+        service_hash.values << project_id
+      end
+
+      Project.transaction do
+        bulk_insert_services(service_hash.keys << 'project_id', service_list)
+        run_callbacks(batch)
+      end
+    end
+
+    def project_ids_batch
+      Project.connection.select_values(
+        <<-SQL
+          SELECT id
+          FROM projects
+          WHERE NOT EXISTS (
+            SELECT true
+            FROM services
+            WHERE services.project_id = projects.id
+            AND services.type = '#{@template.type}'
+          )
+          AND projects.pending_delete = false
+          AND projects.archived = false
+          LIMIT #{BATCH_SIZE}
+      SQL
+      )
+    end
+
+    def bulk_insert_services(columns, values_array)
+      ActiveRecord::Base.connection.execute(
+        <<-SQL.strip_heredoc
+          INSERT INTO services (#{columns.join(', ')})
+          VALUES #{values_array.map { |tuple| "(#{tuple.join(', ')})" }.join(', ')}
+      SQL
+      )
+    end
+
+    def service_hash
+      @service_hash ||=
+        begin
+          template_hash = @template.as_json(methods: :type).except('id', 'template', 'project_id')
+
+          template_hash.each_with_object({}) do |(key, value), service_hash|
+            value = value.is_a?(Hash) ? value.to_json : value
+
+            service_hash[ActiveRecord::Base.connection.quote_column_name(key)] =
+              ActiveRecord::Base.sanitize(value)
+          end
+        end
+    end
+
+    def run_callbacks(batch)
+      if active_external_issue_tracker?
+        Project.where(id: batch).update_all(has_external_issue_tracker: true)
+      end
+
+      if active_external_wiki?
+        Project.where(id: batch).update_all(has_external_wiki: true)
+      end
+    end
+
+    def active_external_issue_tracker?
+      @template.issue_tracker? && !@template.default
+    end
+
+    def active_external_wiki?
+      @template.type == 'ExternalWikiService'
+    end
+  end
+end
diff --git a/app/workers/propagate_service_template_worker.rb b/app/workers/propagate_service_template_worker.rb
new file mode 100644
index 00000000000..5ce0e0405d0
--- /dev/null
+++ b/app/workers/propagate_service_template_worker.rb
@@ -0,0 +1,21 @@
+# Worker for updating any project specific caches.
+class PropagateServiceTemplateWorker
+  include Sidekiq::Worker
+  include DedicatedSidekiqQueue
+
+  LEASE_TIMEOUT = 4.hours.to_i
+
+  def perform(template_id)
+    return unless try_obtain_lease_for(template_id)
+
+    Projects::PropagateServiceTemplate.propagate(Service.find_by(id: template_id))
+  end
+
+  private
+
+  def try_obtain_lease_for(template_id)
+    Gitlab::ExclusiveLease.
+      new("propagate_service_template_worker:#{template_id}", timeout: LEASE_TIMEOUT).
+      try_obtain
+  end
+end
diff --git a/changelogs/unreleased/fix-admin-integrations.yml b/changelogs/unreleased/fix-admin-integrations.yml
new file mode 100644
index 00000000000..7689623501f
--- /dev/null
+++ b/changelogs/unreleased/fix-admin-integrations.yml
@@ -0,0 +1,4 @@
+---
+title: Fix new admin integrations not taking effect on existing projects
+merge_request:
+author:
diff --git a/config/sidekiq_queues.yml b/config/sidekiq_queues.yml
index c3bd73533d0..433381e79d3 100644
--- a/config/sidekiq_queues.yml
+++ b/config/sidekiq_queues.yml
@@ -53,3 +53,4 @@
   - [pages, 1]
   - [system_hook_push, 1]
   - [update_user_activity, 1]
+  - [propagate_service_template, 1]
diff --git a/spec/controllers/admin/services_controller_spec.rb b/spec/controllers/admin/services_controller_spec.rb
index e5cdd52307e..c94616d8508 100644
--- a/spec/controllers/admin/services_controller_spec.rb
+++ b/spec/controllers/admin/services_controller_spec.rb
@@ -23,4 +23,36 @@ describe Admin::ServicesController do
       end
     end
   end
+
+  describe "#update" do
+    let(:project) { create(:empty_project) }
+    let!(:service) do
+      RedmineService.create(
+        project: project,
+        active: false,
+        template: true,
+        properties: {
+          project_url: 'http://abc',
+          issues_url: 'http://abc',
+          new_issue_url: 'http://abc'
+        }
+      )
+    end
+
+    it 'calls the propagation worker when service is active' do
+      expect(PropagateServiceTemplateWorker).to receive(:perform_async).with(service.id)
+
+      put :update, id: service.id, service: { active: true }
+
+      expect(response).to have_http_status(302)
+    end
+
+    it 'does not call the propagation worker when service is not active' do
+      expect(PropagateServiceTemplateWorker).not_to receive(:perform_async)
+
+      put :update, id: service.id, service: { properties: {} }
+
+      expect(response).to have_http_status(302)
+    end
+  end
 end
diff --git a/spec/services/projects/propagate_service_template_spec.rb b/spec/services/projects/propagate_service_template_spec.rb
new file mode 100644
index 00000000000..90eff3bbc1e
--- /dev/null
+++ b/spec/services/projects/propagate_service_template_spec.rb
@@ -0,0 +1,103 @@
+require 'spec_helper'
+
+describe Projects::PropagateServiceTemplate, services: true do
+  describe '.propagate' do
+    let!(:service_template) do
+      PushoverService.create(
+        template: true,
+        active: true,
+        properties: {
+          device: 'MyDevice',
+          sound: 'mic',
+          priority: 4,
+          user_key: 'asdf',
+          api_key: '123456789'
+        })
+    end
+
+    let!(:project) { create(:empty_project) }
+
+    it 'creates services for projects' do
+      expect(project.pushover_service).to be_nil
+
+      described_class.propagate(service_template)
+
+      expect(project.reload.pushover_service).to be_present
+    end
+
+    it 'creates services for a project that has another service' do
+      BambooService.create(
+        template: true,
+        active: true,
+        project: project,
+        properties: {
+          bamboo_url: 'http://gitlab.com',
+          username: 'mic',
+          password: "password",
+          build_key: 'build'
+        }
+      )
+
+      expect(project.pushover_service).to be_nil
+
+      described_class.propagate(service_template)
+
+      expect(project.reload.pushover_service).to be_present
+    end
+
+    it 'does not create the service if it exists already' do
+      other_service = BambooService.create(
+        template: true,
+        active: true,
+        properties: {
+          bamboo_url: 'http://gitlab.com',
+          username: 'mic',
+          password: "password",
+          build_key: 'build'
+        }
+      )
+
+      Service.build_from_template(project.id, service_template).save!
+      Service.build_from_template(project.id, other_service).save!
+
+      expect { described_class.propagate(service_template) }.
+        not_to change { Service.count }
+    end
+
+    it 'creates the service containing the template attributes' do
+      described_class.propagate(service_template)
+
+      expect(project.pushover_service.properties).to eq(service_template.properties)
+    end
+
+    describe 'bulk update' do
+      it 'creates services for all projects' do
+        project_total = 5
+        stub_const 'Projects::PropagateServiceTemplate::BATCH_SIZE', 3
+
+        project_total.times { create(:empty_project) }
+
+        expect { described_class.propagate(service_template) }.
+          to change { Service.count }.by(project_total + 1)
+      end
+    end
+
+    describe 'external tracker' do
+      it 'updates the project external tracker' do
+        service_template.update!(category: 'issue_tracker', default: false)
+
+        expect { described_class.propagate(service_template) }.
+          to change { project.reload.has_external_issue_tracker }.to(true)
+      end
+    end
+
+    describe 'external wiki' do
+      it 'updates the project external tracker' do
+        service_template.update!(type: 'ExternalWikiService')
+
+        expect { described_class.propagate(service_template) }.
+          to change { project.reload.has_external_wiki }.to(true)
+      end
+    end
+  end
+end
diff --git a/spec/workers/propagate_service_template_worker_spec.rb b/spec/workers/propagate_service_template_worker_spec.rb
new file mode 100644
index 00000000000..7040d5ef81c
--- /dev/null
+++ b/spec/workers/propagate_service_template_worker_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+describe PropagateServiceTemplateWorker do
+  let!(:service_template) do
+    PushoverService.create(
+      template: true,
+      active: true,
+      properties: {
+        device: 'MyDevice',
+        sound: 'mic',
+        priority: 4,
+        user_key: 'asdf',
+        api_key: '123456789'
+      })
+  end
+
+  before do
+    allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:try_obtain).
+      and_return(true)
+  end
+
+  describe '#perform' do
+    it 'calls the propagate service with the template' do
+      expect(Projects::PropagateServiceTemplate).to receive(:propagate).with(service_template)
+
+      subject.perform(service_template.id)
+    end
+  end
+end