Move logic to active_record_lifecycle

config/initializers/active_record_lifecycle.rb

@@ -12,6 +12,14 @@ if defined?(ActiveRecord::Base) && !Gitlab::Runtime.sidekiq?
   end
 end
 
+if defined?(ActiveRecord::Base) && Gitlab::Runtime.web_server?
+  Gitlab::Cluster::LifecycleEvents.on_before_fork do
+    ActiveSupport.on_load(:active_record) do
+      raise 'ActiveRecord connection not established. Unable to start.' unless ::ActiveRecord::Base.connected?
+    end
+  end
+end
+
 if defined?(ActiveRecord::Base)
   Gitlab::Cluster::LifecycleEvents.on_before_fork do
     # the following is highly recommended for Rails + "preload_app true"

lib/gitlab/cluster/mixins/puma_cluster.rb

@@ -6,7 +6,6 @@ module Gitlab
       module PumaCluster
         def self.prepended(base)
           raise 'missing method Puma::Cluster#stop_workers' unless base.method_defined?(:stop_workers)
-          raise 'ActiveRecord connection not established. Unable to start.' unless ActiveRecord::Base.connected?
         end
 
         # This looks at internal status of `Puma::Cluster`

lib/gitlab/cluster/mixins/unicorn_http_server.rb

@@ -8,8 +8,6 @@ module Gitlab
           unless base.method_defined?(:reexec) && base.method_defined?(:stop)
             raise 'missing method Unicorn::HttpServer#reexec or Unicorn::HttpServer#stop'
           end
-
-          raise 'ActiveRecord connection not established. Unable to start.' unless ::ActiveRecord::Base.connected?
         end
 
         def reexec