diff --git a/doc/source/deprecation.rst b/doc/source/deprecation.rst
index 6d3fff3c1..aab28b74d 100644
--- a/doc/source/deprecation.rst
+++ b/doc/source/deprecation.rst
@@ -32,6 +32,18 @@ Before deprecating a feature in Zuul which is used by `zuul-jobs`, the
 usage of the feature must be removed from `zuul-jobs` according to the
 deprecation policy described above.
 
+Python Version Policy
+=====================
+
+``zuul-jobs`` targets Python 2.7 onwards and Python 3.5 onwards (note
+this differs slightly from Ansible upstream, where the policy is 2.6
+onwards unless libraries depend on newer features.  `zuul-jobs` does
+not support Python 2.6).
+
+Library code should be written to be compatible with both.  There are
+some tips on this in `Ansible and Python 3
+<https://docs.ansible.com/ansible/2.5/dev_guide/developing_python_3.html>`__.
+
 .. _zuul-announce: http://lists.zuul-ci.org/cgi-bin/mailman/listinfo/zuul-announce
 .. _zuul-discuss: http://lists.zuul-ci.org/cgi-bin/mailman/listinfo/zuul-discuss
 
diff --git a/roles/__init__.py b/roles/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/roles/htmlify-logs/__init__.py b/roles/htmlify-logs/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/roles/multi-node-known-hosts/__init__.py b/roles/multi-node-known-hosts/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/roles/sphinx/__init__.py b/roles/sphinx/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/roles/tox/__init__.py b/roles/tox/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/roles/upload-afs/__init__.py b/roles/upload-afs/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/roles/upload-logs-swift/__init__.py b/roles/upload-logs-swift/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/roles/validate-host/__init__.py b/roles/validate-host/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tox.ini b/tox.ini
index bcb350d48..cf27ff9d1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,6 +10,9 @@ deps = -r{toxinidir}/test-requirements.txt
 commands = stestr run {posargs}
            stestr slowest
 
+[testenv:py27]
+basepython = python2.7
+
 [testenv:bindep]
 # Do not install any requirements. We want this to be fast and work even if
 # system dependencies are missing, since it's used to tell you what system