diff --git a/defaults/main.yml b/defaults/main.yml
index 2f53b96..1b7805e 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -33,11 +33,12 @@ mistral_package_state: latest
 mistral_role_project_group: mistral_all
 
 # Source package builds
-mistral_developer_mode: false
 mistral_git_repo: https://git.openstack.org/openstack/mistral
 mistral_git_install_branch: master
-mistral_developer_constraints:
+mistral_upper_constraints_url: "{{ requirements_git_url | default('https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt?h=' ~ requirements_git_install_branch | default('master')) }}"
+mistral_git_constraints:
   - "git+{{ mistral_git_repo }}@{{ mistral_git_install_branch }}#egg=mistral"
+  - "--constraint {{ mistral_upper_constraints_url }}"
 mistral_pip_packages:
   - mistral
   - PyMySQL
@@ -47,16 +48,8 @@ mistral_optional_oslomsg_amqp1_pip_packages:
   - oslo.messaging[amqp1]
 mistral_venv_tag: "{{ venv_tag | default('untagged') }}"
 mistral_bin: "{{ _mistral_bin }}"
-# TODO(odyssey4me):
-# This can be simplified once all the roles are using
-# python_venv_build. We can then switch to using a
-# set of constraints in pip.conf inside the venv,
-# perhaps prepared by giving a giving a list of
-# constraints to the role.
-mistral_pip_install_args: >-
-  {{ mistral_developer_mode | ternary(pip_install_developer_constraints | default('--constraint /opt/developer-pip-constraints.txt'), '') }}
-  {{ (pip_install_upper_constraints is defined) | ternary('--constraint ' + pip_install_upper_constraints | default(''), '') }}
-  {{ pip_install_options | default('') }}
+
+mistral_pip_install_args: "{{ pip_install_options | default('') }}"
 
 # Services
 mistral_services:
@@ -161,3 +154,6 @@ mistral_service_internaluri_proto: "{{ openstack_service_internaluri_proto | def
 mistral_service_internalurl: "{{ mistral_service_internaluri_proto }}://{{ internal_lb_vip_address }}:{{ mistral_service_port }}/v2"
 mistral_service_adminuri_proto: "{{ openstack_service_adminuri_proto | default(mistral_service_proto) }}"
 mistral_service_adminurl: "{{ mistral_service_adminuri_proto }}://{{ internal_lb_vip_address }}:{{ mistral_service_port }}/v2"
+
+# Specific pip packages provided by the user
+mistral_user_pip_packages: []
diff --git a/tasks/mistral_install.yml b/tasks/mistral_install.yml
index 2999a57..c78c77a 100644
--- a/tasks/mistral_install.yml
+++ b/tasks/mistral_install.yml
@@ -70,8 +70,22 @@
   retries: 5
   delay: 2
 
-- name: Install mistral packages from PIP
-  include_tasks: mistral_install_source.yml
+- name: Install the python venv
+  import_role:
+    name: "python_venv_build"
+  vars:
+    venv_build_constraints: "{{ mistral_git_constraints }}"
+    venv_build_distro_package_list: "{{ mistral_devel_distro_packages }}"
+    venv_install_destination_path: "{{ mistral_bin | dirname }}"
+    venv_pip_install_args: "{{ mistral_pip_install_args }}"
+    venv_pip_packages: >-
+      {{ mistral_pip_packages |
+           union(mistral_user_pip_packages) |
+             union(((mistral_oslomsg_amqp1_enabled | bool) | ternary(mistral_optional_oslomsg_amqp1_pip_packages, []))) }}
+    venv_facts_when_changed:
+      - section: "mistral"
+        option: "venv_tag"
+        value: "{{ mistral_venv_tag }}"
   when: mistral_install_method == 'source'
 
 - name: Record the need for a service restart
diff --git a/tasks/mistral_install_source.yml b/tasks/mistral_install_source.yml
deleted file mode 100644
index 1e77526..0000000
--- a/tasks/mistral_install_source.yml
+++ /dev/null
@@ -1,52 +0,0 @@
----
-# Copyright 2019, VEXXHOST, Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# TODO(odyssey4me):
-# This can be simplified once all the roles are using
-# python_venv_build. We can then switch to using a
-# set of constraints in pip.conf inside the venv,
-# perhaps prepared by giving a giving a list of
-# constraints to the role.
-- name: Create developer mode constraint file
-  copy:
-    dest: "/opt/developer-pip-constraints.txt"
-    content: |
-      {% for item in mistral_developer_constraints %}
-      {{ item }}
-      {% endfor %}
-  when: mistral_developer_mode | bool
-
-- name: Ensure remote wheel building is disabled in developer mode
-  set_fact:
-    venv_build_host: "{{ inventory_hostname }}"
-  when: mistral_developer_mode | bool
-
-- name: Install the python venv
-  include_role:
-    name: "python_venv_build"
-  vars:
-    venv_build_distro_package_list: "{{ mistral_devel_distro_packages }}"
-    venv_install_destination_path: "{{ mistral_bin | dirname }}"
-    venv_pip_install_args: "{{ mistral_pip_install_args }}"
-    venv_pip_packages: >-
-      {{ mistral_pip_packages +
-         (mistral_oslomsg_amqp1_enabled | bool) | ternary(mistral_optional_oslomsg_amqp1_pip_packages, []) }}
-    venv_facts_when_changed:
-      - section: "mistral"
-        option: "need_service_restart"
-        value: True
-      - section: "mistral"
-        option: "venv_tag"
-        value: "{{ mistral_venv_tag }}"