diff --git a/requirements.txt b/requirements.txt
index ad2e2a291..cb31cee1d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,6 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
 pbr>=0.6,!=0.7,<1.0
 
 Paste
@@ -9,7 +12,7 @@ Babel>=1.3
 eventlet>=0.15.1
 greenlet>=0.3.2
 httplib2>=0.7.5
-requests>=1.2.1
+requests>=1.2.1,!=2.4.0
 iso8601>=0.1.9
 jsonrpclib
 Jinja2
@@ -28,4 +31,4 @@ oslo.db>=0.4.0  # Apache-2.0
 oslo.messaging>=1.4.0.0a3
 oslo.rootwrap>=1.3.0.0a1
 
-python-novaclient>=2.17.0
+python-novaclient>=2.18.0
diff --git a/test-requirements.txt b/test-requirements.txt
index 957547adf..d01760d16 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,3 +1,6 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
 hacking>=0.9.2,<0.10
 
 cliff>=1.6.0