Run tox in venv in case of building images

tox depends on virtualenv, when it's installed using pip - it tries to upgrade
virtualenv, and then fails.

Change-Id: Ic9566778f87f8b81563ed012e651cef50d1baa38

tests/pre.yml

@@ -36,6 +36,14 @@
           - python-virtualenv
           - python-wheel
 
+    - name: Install virtualenv on Debian systems
+      package:
+        name:
+          - virtualenv
+      become: true
+      when:
+        ansible_os_family == "Debian"
+
     - name: Ensure latest pip is installed
       become: true
       pip:

tests/run.yml

@@ -47,6 +47,7 @@
     - name: Ensure tox is installed
       pip:
         name: tox
+        virtualenv: "{{ ansible_env.HOME }}/tox-venv"
       when: need_build_image
       become: true
 
@@ -191,6 +192,7 @@
         TAG: "{{ build_image_tag }}"
         KOLLA_SRC_DIR: "{{ ansible_env.HOME }}/src/opendev.org/openstack/kolla"
         ACTION: "{{ scenario }}"
+        TOX_VENV: "{{ ansible_env.HOME }}/tox-venv"
         UPPER_CONSTRAINTS: "{{ ansible_env.HOME }}/src/opendev.org/openstack/requirements/upper-constraints.txt"
 
     # At this point we have generated all necessary configuration, and are

tools/setup_gate.sh

@@ -150,7 +150,7 @@ function prepare_images {
     fi
     sudo docker run -d -p 4000:5000 --restart=always -v /opt/kolla_registry/:/var/lib/registry --name registry registry:2
     pushd "${KOLLA_SRC_DIR}"
-    sudo tox -e "build-${BASE_DISTRO}-${INSTALL_TYPE}"
+    sudo $TOX_VENV/bin/tox -e "build-${BASE_DISTRO}-${INSTALL_TYPE}"
     popd
 }