diff --git a/config/initializers/0_license.rb b/config/initializers/0_license.rb
new file mode 100644
index 00000000000..c4f9a2bc74e
--- /dev/null
+++ b/config/initializers/0_license.rb
@@ -0,0 +1,19 @@
+require_dependency 'lib/gitlab'
+
+Gitlab.ee do
+  begin
+    public_key_file = File.read(Rails.root.join(".license_encryption_key.pub"))
+    public_key = OpenSSL::PKey::RSA.new(public_key_file)
+    Gitlab::License.encryption_key = public_key
+  rescue
+    warn "WARNING: No valid license encryption key provided."
+  end
+
+  # Needed to run migration
+  if ActiveRecord::Base.connected? && ActiveRecord::Base.connection.data_source_exists?('licenses')
+    message = LicenseHelper.license_message(signed_in: true, is_admin: true, in_html: false)
+    if ::License.block_changes? && message.present?
+      warn "WARNING: #{message}"
+    end
+  end
+end
diff --git a/config/initializers/elastic_client_setup.rb b/config/initializers/elastic_client_setup.rb
new file mode 100644
index 00000000000..0f6d494ba3c
--- /dev/null
+++ b/config/initializers/elastic_client_setup.rb
@@ -0,0 +1,48 @@
+# Be sure to restart your server when you modify this file.
+
+require 'gitlab/current_settings'
+
+Gitlab.ee do
+  Elasticsearch::Model::Response::Records.prepend GemExtensions::Elasticsearch::Model::Response::Records
+  Elasticsearch::Model::Adapter::Multiple::Records.prepend GemExtensions::Elasticsearch::Model::Adapter::Multiple::Records
+  Elasticsearch::Model::Indexing::InstanceMethods.prepend GemExtensions::Elasticsearch::Model::Indexing::InstanceMethods
+
+  module Elasticsearch
+    module Model
+      module Client
+        # This mutex is only used to synchronize *creation* of a new client, so
+        # all including classes can share the same client instance
+        CLIENT_MUTEX = Mutex.new
+
+        cattr_accessor :cached_client
+        cattr_accessor :cached_config
+
+        module ClassMethods
+          # Override the default ::Elasticsearch::Model::Client implementation to
+          # return a client configured from application settings. All including
+          # classes will use the same instance, which is refreshed automatically
+          # if the settings change.
+          #
+          # _client is present to match the arity of the overridden method, where
+          # it is also not used.
+          #
+          # @return [Elasticsearch::Transport::Client]
+          def client(_client = nil)
+            store = ::Elasticsearch::Model::Client
+
+            store::CLIENT_MUTEX.synchronize do
+              config = Gitlab::CurrentSettings.elasticsearch_config
+
+              if store.cached_client.nil? || config != store.cached_config
+                store.cached_client = ::Gitlab::Elastic::Client.build(config)
+                store.cached_config = config
+              end
+            end
+
+            store.cached_client
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/config/initializers/geo.rb b/config/initializers/geo.rb
new file mode 100644
index 00000000000..b820f629d92
--- /dev/null
+++ b/config/initializers/geo.rb
@@ -0,0 +1,15 @@
+Gitlab.ee do
+  if File.exist?(Rails.root.join('config/database_geo.yml'))
+    Rails.application.configure do
+      config.geo_database = config_for(:database_geo)
+    end
+  end
+
+  begin
+    if Gitlab::Geo.connected? && Gitlab::Geo.primary?
+      Gitlab::Geo.current_node&.update_clone_url!
+    end
+  rescue => e
+    warn "WARNING: Unable to check/update clone_url_prefix for Geo: #{e}"
+  end
+end
diff --git a/config/initializers/load_balancing.rb b/config/initializers/load_balancing.rb
new file mode 100644
index 00000000000..1ac422a6e8a
--- /dev/null
+++ b/config/initializers/load_balancing.rb
@@ -0,0 +1,23 @@
+# We need to run this initializer after migrations are done so it doesn't fail on CI
+
+Gitlab.ee do
+  if ActiveRecord::Base.connected? && ActiveRecord::Base.connection.data_source_exists?('licenses')
+    if Gitlab::Database::LoadBalancing.enable?
+      Gitlab::Database.disable_prepared_statements
+
+      Gitlab::Application.configure do |config|
+        config.middleware.use(Gitlab::Database::LoadBalancing::RackMiddleware)
+      end
+
+      Gitlab::Database::LoadBalancing.configure_proxy
+
+      # This needs to be executed after fork of clustered processes
+      Gitlab::Cluster::LifecycleEvents.on_worker_start do
+        # Service discovery must be started after configuring the proxy, as service
+        # discovery depends on this.
+        Gitlab::Database::LoadBalancing.start_service_discovery
+      end
+
+    end
+  end
+end
diff --git a/config/initializers/sidekiq_cluster.rb b/config/initializers/sidekiq_cluster.rb
new file mode 100644
index 00000000000..cbf8caef706
--- /dev/null
+++ b/config/initializers/sidekiq_cluster.rb
@@ -0,0 +1,18 @@
+if ENV['ENABLE_SIDEKIQ_CLUSTER'] && Gitlab.ee?
+  Thread.new do
+    Thread.current.abort_on_exception = true
+
+    parent = Process.ppid
+
+    loop do
+      sleep(5)
+
+      # In cluster mode it's possible that the master process is SIGKILL'd. In
+      # this case the parent PID changes and we need to terminate ourselves.
+      if Process.ppid != parent
+        Process.kill(:TERM, Process.pid)
+        break
+      end
+    end
+  end
+end