Call your existing LDAP server 'main'

config/gitlab.yml.example

@@ -105,6 +105,15 @@ production: &base
   ldap:
     enabled: false
     servers:
+      ##########################################################################
+      #
+      # Since GitLab 7.4, LDAP servers get ID's (below the ID is 'main'). GitLab
+      # Enterprise Edition now supports connecting to multiple LDAP servers.
+      #
+      # If you are updating from the old (pre-7.4) syntax, you MUST give your
+      # old server the ID 'main'.
+      #
+      ##########################################################################
       main: # 'main' is the GitLab 'provider ID' of this LDAP server
         ## label
         #

config/initializers/1_settings.rb

@@ -81,10 +81,6 @@ if Settings.ldap['enabled'] || Rails.env.test?
     server['provider_name'] ||= "ldap#{key}".downcase
     server['provider_class'] = OmniAuth::Utils.camelize(server['provider_name'])
   end
-
-  unless Settings.ldap['servers'].select{ |k, server| server['provider_name'] == "ldapmain"}.any?
-    raise "Wrong LDAP configuration. The 'main' LDAP section is missing"
-  end
 end