diff --git a/Vagrantfile b/Vagrantfile
index 7acf718d..bf2400c1 100644
--- a/Vagrantfile
+++ b/Vagrantfile
@@ -51,13 +51,8 @@ Vagrant.configure(2) do |config|
     leap150.vm.box = "opensuse/openSUSE-15.0-x86_64"
   end
 
-  config.vm.define "opensuse151" do |leap150|
-    leap150.vm.box = "opensuse/openSUSE-15.1-x86_64"
-  end
-
-  config.vm.define "ubuntu1604" do |xenial|
-    xenial.disksize.size = "40GB"
-    xenial.vm.box = "ubuntu/xenial64"
+  config.vm.define "opensuse151" do |leap151|
+    leap151.vm.box = "opensuse/openSUSE-15.1-x86_64"
   end
 
   config.vm.define "ubuntu1804" do |bionic|
diff --git a/doc/requirements.txt b/doc/requirements.txt
index 9920d5a0..12390ff1 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -2,7 +2,13 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-# this is required for the docs build jobs
+# WARNING:
+# This file is maintained in the openstack-ansible-tests repository.
+# https://opendev.org/openstack/openstack-ansible-tests/src/branch/master/sync/doc/requirements.txt
+# If you need to modify this file, update the one in the
+# openstack-ansible-tests repository. Once it merges there, the changes will
+# automatically be proposed to all the repositories which use it.
+
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
 sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4'  # BSD
 openstackdocstheme>=1.18.1 # Apache-2.0