diff --git a/run_tests.sh b/run_tests.sh
index 19faff741e..15e3a9a8ad 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -61,7 +61,6 @@ function usage {
 #
 root=`pwd -P`
 venv=$root/.venv
-venv_env_version=$venv/environments
 with_venv=tools/with_venv.sh
 included_dirs="openstack_dashboard horizon"
 
@@ -96,6 +95,13 @@ check_only=0
 pseudo=0
 manage=0
 
+# NOTE(tonyb): the release team will automatically update tox.ini to point at
+# the correct requirements branch when creating stable/* from master.  So go to
+# a little effort to get the deault from there to avoid dift and having to
+# update this when branching
+_default_uc=$(sed -n 's/^.*{env:UPPER_CONSTRAINTS_FILE\:\([^}]*\)}.*$/\1/p' \
+              tox.ini | head -n1)
+
 # Jenkins sets a "JOB_NAME" variable, if it's not set, we'll make it "default"
 [ "$JOB_NAME" ] || JOB_NAME="default"
 
@@ -241,39 +247,6 @@ function destroy_venv {
   echo "Virtualenv removed."
 }
 
-function environment_check {
-  echo "Checking environment."
-  if [ -f $venv_env_version ]; then
-    set +o errexit
-    cat requirements.txt test-requirements.txt | cmp $venv_env_version - > /dev/null
-    local env_check_result=$?
-    set -o errexit
-    if [ $env_check_result -eq 0 ]; then
-      # If the environment exists and is up-to-date then set our variables
-      command_wrapper="${root}/${with_venv}"
-      echo "Environment is up to date."
-      return 0
-    fi
-  fi
-
-  if [ $always_venv -eq 1 ]; then
-    install_venv
-  else
-    if [ ! -e ${venv} ]; then
-      echo -e "Environment not found. Install? (Y/n) \c"
-    else
-      echo -e "Your environment appears to be out of date. Update? (Y/n) \c"
-    fi
-    read update_env
-    if [ "x$update_env" = "xY" -o "x$update_env" = "x" -o "x$update_env" = "xy" ]; then
-      install_venv
-    else
-      # Set our command wrapper anyway.
-      command_wrapper="${root}/${with_venv}"
-    fi
-  fi
-}
-
 function sanity_check {
   # Anything that should be determined prior to running the tests, server, etc.
   # Don't sanity-check anything environment-related in -N flag is set
@@ -322,6 +295,7 @@ function restore_environment {
 
 function install_venv {
   # Install with install_venv.py
+  export UPPER_CONSTRAINTS_FILE=${UPPER_CONSTRAINTS_FILE:-$_default_uc}
   export PIP_DOWNLOAD_CACHE=${PIP_DOWNLOAD_CACHE-/tmp/.pip_download_cache}
   export PIP_USE_MIRRORS=true
   if [ $quiet -eq 1 ]; then
@@ -334,7 +308,6 @@ function install_venv {
   # Make sure it worked and record the environment version
   sanity_check
   chmod -R 754 $venv
-  cat requirements.txt test-requirements.txt > $venv_env_version
 }
 
 function run_tests {
@@ -530,8 +503,8 @@ if [ $never_venv -eq 0 ]; then
     destroy_venv
   fi
 
-  # Then check if it's up-to-date
-  environment_check
+  # Create or update venv.
+  install_venv
 
   # Create a backup of the up-to-date environment if desired
   if [ $backup_env -eq 1 ]; then
diff --git a/tools/install_venv.py b/tools/install_venv.py
index e96521ea23..d857b1eafe 100644
--- a/tools/install_venv.py
+++ b/tools/install_venv.py
@@ -58,8 +58,10 @@ def main(argv):
     test_requires = os.path.join(root, 'test-requirements.txt')
     py_version = "python%s.%s" % (sys.version_info[0], sys.version_info[1])
     project = 'OpenStack'
+    constraints = os.environ.get('UPPER_CONSTRAINTS_FILE')
     install = install_venv.InstallVenv(root, venv, pip_requires, test_requires,
-                                       py_version, project)
+                                       py_version, project,
+                                       constraints=constraints)
     options = install.parse_args(argv)
     install.check_python_version()
     install.check_dependencies()
diff --git a/tools/install_venv_common.py b/tools/install_venv_common.py
index 46822e3293..3a2e33683d 100644
--- a/tools/install_venv_common.py
+++ b/tools/install_venv_common.py
@@ -34,9 +34,10 @@ class InstallVenv(object):
 
     def __init__(self, root, venv, requirements,
                  test_requirements, py_version,
-                 project):
+                 project, constraints=None):
         self.root = root
         self.venv = venv
+        self.constraints = constraints
         self.requirements = requirements
         self.test_requirements = test_requirements
         self.py_version = py_version
@@ -104,17 +105,19 @@ class InstallVenv(object):
             pass
 
     def pip_install(self, *args):
-        self.run_command(['tools/with_venv.sh',
-                         'pip', 'install', '--upgrade'] + list(args),
-                         redirect_output=False)
+        cmd = ['tools/with_venv.sh', 'pip', 'install', '--upgrade']
+        if self.constraints:
+            cmd += ['-c', self.constraints]
+        self.run_command(cmd + list(args), redirect_output=False)
 
     def install_dependencies(self):
         print('Installing dependencies with pip (this can take a while)...')
 
         # First things first, make sure our venv has the latest pip and
         # setuptools and pbr
-        self.pip_install('pip>=1.4')
+        self.pip_install('pip>=7.1.0')
         self.pip_install('setuptools')
+        self.pip_install('wheel')
         self.pip_install('pbr')
 
         self.pip_install('-r', self.requirements, '-r', self.test_requirements)