Remove duplicate read-only flash message on admin pages

app/controllers/admin/application_controller.rb

@@ -3,23 +3,9 @@
 # Automatically sets the layout and ensures an administrator is logged in
 class Admin::ApplicationController < ApplicationController
   before_action :authenticate_admin!
-  before_action :display_read_only_information
   layout 'admin'
 
   def authenticate_admin!
     render_404 unless current_user.admin?
   end
-
-  def display_read_only_information
-    return unless Gitlab::Database.read_only?
-
-    flash.now[:notice] = read_only_message
-  end
-
-  private
-
-  # Overridden in EE
-  def read_only_message
-    _('You are on a read-only GitLab instance.')
-  end
 end

changelogs/unreleased-ee/tc-geo-remove-double-banner.yml

+---
+title: Remove duplicate read-only flash message on admin pages
+merge_request: 3495
+author:
+type: fixed

ee/app/controllers/ee/admin/application_controller.rb

-module EE
-  module Admin
-    module ApplicationController
-      def read_only_message
-        raise NotImplementedError unless defined?(super)
-
-        return super unless Gitlab::Geo.secondary_with_primary?
-
-        link_to_primary_node = view_context.link_to('primary node', Gitlab::Geo.primary_node.url)
-        (_('You are on a read-only GitLab instance. If you want to make any changes, you must visit the %{link_to_primary_node}.') % { link_to_primary_node: link_to_primary_node }).html_safe
-      end
-    end
-  end
-end