diff --git a/tox.ini b/tox.ini
index b44b3e0..6d596e3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,13 +4,14 @@
 skipsdist = True
 
 [testenv]
+sitepackages = True
 setenv = VIRTUAL_ENV={envdir}
          LANG=en_US.UTF-8
          LANGUAGE=en_US:en
          LC_ALL=C
          OS_TEST_PATH=./tempest/test_discover
 usedevelop = True
-install_command = pip install -U {opts} {packages}
+install_command = pip install {opts} {packages}
 
 [testenv:py26]
 setenv = OS_TEST_PATH=./tempest/tests
@@ -25,38 +26,32 @@
 commands = python setup.py test --slowest --testr-arg='tempest\.tests {posargs}'
 
 [testenv:all]
-sitepackages = True
 setenv = VIRTUAL_ENV={envdir}
 commands =
   python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:full]
-sitepackages = True
 # The regex below is used to select which tests to run and exclude the slow tag:
 # See the testrepostiory bug: https://bugs.launchpad.net/testrepository/+bug/1208610
 commands =
   bash tools/pretty_tox.sh '(?!.*\[.*\bslow\b.*\])(^tempest\.(api|scenario|thirdparty|cli)) {posargs}'
 
 [testenv:testr-full]
-sitepackages = True
 commands =
   bash tools/pretty_tox.sh '(?!.*\[.*\bslow\b.*\])(^tempest\.(api|scenario|thirdparty|cli)) {posargs}'
 
 [testenv:heat-slow]
-sitepackages = True
 setenv = OS_TEST_TIMEOUT=1200
 # The regex below is used to select heat api/scenario tests tagged as slow.
 commands =
   bash tools/pretty_tox_serial.sh '(?=.*\[.*\bslow\b.*\])(^tempest\.(api|scenario)\.orchestration) {posargs}'
 
 [testenv:large-ops]
-sitepackages = True
 commands =
   python setup.py testr --slowest --testr-args='tempest.scenario.test_large_ops {posargs}'
 
 
 [testenv:py26-full]
-sitepackages = True
 setenv = VIRTUAL_ENV={envdir}
          NOSE_WITH_OPENSTACK=1
          NOSE_OPENSTACK_COLOR=1
@@ -81,12 +76,10 @@
   nosetests --logging-format '%(asctime)-15s %(message)s' --with-xunit -sv --attr=type=smoke --xunit-file=nosetests-smoke.xml tempest {posargs}
 
 [testenv:smoke]
-sitepackages = True
 commands =
    bash tools/pretty_tox.sh '(?!.*\[.*\bslow\b.*\])((smoke)|(^tempest\.scenario)) {posargs}'
 
 [testenv:smoke-serial]
-sitepackages = True
 # This is still serial because neutron doesn't work with parallel. See:
 # https://bugs.launchpad.net/tempest/+bug/1216076 so the neutron smoke
 # job would fail if we moved it to parallel.
@@ -94,7 +87,6 @@
    bash tools/pretty_tox_serial.sh '(?!.*\[.*\bslow\b.*\])((smoke)|(^tempest\.scenario)) {posargs}'
 
 [testenv:stress]
-sitepackages = True
 commands =
     python -m tempest/stress/run_stress -a -d 3600 -S