Remove uniqueness constraint from url

So that secondaries can use the same URL.

db/schema.rb

@@ -1389,7 +1389,6 @@ ActiveRecord::Schema.define(version: 20190426180107) do
     t.index ["access_key"], name: "index_geo_nodes_on_access_key", using: :btree
     t.index ["name"], name: "index_geo_nodes_on_name", unique: true, using: :btree
     t.index ["primary"], name: "index_geo_nodes_on_primary", using: :btree
-    t.index ["url"], name: "index_geo_nodes_on_url", unique: true, using: :btree
   end
 
   create_table "geo_repositories_changed_events", force: :cascade do |t|

ee/app/models/geo_node.rb

@@ -16,7 +16,7 @@ class GeoNode < ApplicationRecord
   has_one :status, class_name: 'GeoNodeStatus'
 
   validates :name, presence: true, uniqueness: { case_sensitive: false }
-  validates :url, presence: true, uniqueness: { case_sensitive: false }, addressable_url: true
+  validates :url, presence: true, addressable_url: true
   validates :internal_url, addressable_url: true, allow_blank: true, allow_nil: true
 
   validates :primary, uniqueness: { message: 'node already exists' }, if: :primary

ee/db/migrate/20190412183653_remove_url_index_from_geo_nodes.rb

+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RemoveUrlIndexFromGeoNodes < ActiveRecord::Migration[5.0]
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index :geo_nodes, :url
+  end
+
+  def down
+    add_concurrent_index :geo_nodes, :url, unique: true
+  end
+end

ee/spec/models/geo_node_spec.rb

@@ -32,7 +32,6 @@ describe GeoNode, :geo, type: :model do
     it { is_expected.to validate_numericality_of(:minimum_reverification_interval).is_greater_than_or_equal_to(1) }
     it { is_expected.to validate_presence_of(:name) }
     it { is_expected.to validate_presence_of(:url) }
-    it { is_expected.to validate_uniqueness_of(:url).case_insensitive }
     it { is_expected.to validate_uniqueness_of(:name).case_insensitive }
 
     context 'when validating primary node' do
@@ -64,6 +63,13 @@ describe GeoNode, :geo, type: :model do
 
         it { is_expected.not_to be_valid }
       end
+
+      context 'when an existing GeoNode has the same url but different name' do
+        let!(:existing) { new_node }
+        let(:url) { new_node.url }
+
+        it { is_expected.to be_valid }
+      end
     end
 
     context 'when validating internal_url' do