diff --git a/.travis.yml b/.travis.yml
index 5b346ef4..771ff261 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,24 +20,24 @@ services:
 env:
   matrix:
     - INSTANCE: default-debian-10-develop-py3
-    - INSTANCE: default-ubuntu-1804-develop-py3
+    # - INSTANCE: default-ubuntu-1804-develop-py3
     # - INSTANCE: default-centos-7-develop-py3
     # - INSTANCE: default-fedora-30-develop-py3
     # - INSTANCE: default-opensuse-leap-15-develop-py3
     # - INSTANCE: default-amazonlinux-2-develop-py2
-    - INSTANCE: default-debian-9-2019-2-py3
-    - INSTANCE: default-ubuntu-1804-2019-2-py3
+    # - INSTANCE: default-debian-9-2019-2-py3
+    # - INSTANCE: default-ubuntu-1804-2019-2-py3
     # - INSTANCE: default-centos-7-2019-2-py3
     # - INSTANCE: default-fedora-30-2019-2-py3
     # - INSTANCE: default-opensuse-leap-15-2019-2-py3
     # - INSTANCE: default-amazonlinux-2-2019-2-py2
-    - INSTANCE: default-debian-9-2018-3-py2
+    # - INSTANCE: default-debian-9-2018-3-py2
     # - INSTANCE: default-ubuntu-1604-2018-3-py2
     # - INSTANCE: default-centos-7-2018-3-py2
     # - INSTANCE: default-fedora-29-2018-3-py2
     # - INSTANCE: default-opensuse-leap-15-2018-3-py2
     # - INSTANCE: default-amazonlinux-2-2018-3-py2
-    - INSTANCE: default-debian-8-2017-7-py2
+    # - INSTANCE: default-debian-8-2017-7-py2
     # - INSTANCE: default-ubuntu-1604-2017-7-py2
     # - INSTANCE: default-centos-6-2017-7-py2
     # - INSTANCE: default-fedora-29-2017-7-py2
diff --git a/.yamllint b/.yamllint
index 8cee7a46..19cc418c 100644
--- a/.yamllint
+++ b/.yamllint
@@ -12,6 +12,9 @@ ignore: |
   mysql/supported_sections.yaml
 
 rules:
+  empty-values:
+    forbid-in-block-mappings: true
+    forbid-in-flow-mappings: true
   line-length:
     # Increase from default of `80`
     # Based on https://github.com/PyCQA/flake8-bugbear#opinionated-warnings (`B950`)