diff --git a/.gitignore b/.gitignore
index 655d9a2..2f6be65 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 .vagrant
 *.retry
 .rsync
+venv
diff --git a/README.md b/README.md
index 1eee861..dc6b9fd 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,10 @@ An ansible project that solves and documents some of the issues I've faced while
 
 Keeping these examples in a simple, isolated project lets me refer to known working examples, in case I ever have issues while working in more complex projects.
 
+## Ansible version
+
+New versions of Ansible are released regularly. The playbooks in this project are always tested against a specific version, which is specified in requirements.txt (e.g. `ansible==2.2.1.0`).
+
 ## Inventory
 
 See hosts/README.md for notes specific to inventory files.
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..05fc945
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,17 @@
+ansible==2.2.1.0
+appdirs==1.4.0
+cffi==1.9.1
+cryptography==1.7.2
+enum34==1.1.6
+idna==2.2
+ipaddress==1.0.18
+Jinja2==2.8.1
+MarkupSafe==0.23
+packaging==16.8
+paramiko==2.1.1
+pyasn1==0.2.2
+pycparser==2.17
+pycrypto==2.6.1
+pyparsing==2.1.10
+PyYAML==3.12
+six==1.10.0