diff --git a/ansible/group_vars/all/bifrost b/ansible/group_vars/all/bifrost
index fe95cc225..b3dfc3472 100644
--- a/ansible/group_vars/all/bifrost
+++ b/ansible/group_vars/all/bifrost
@@ -7,8 +7,9 @@
 # URL of Bifrost source code repository.
 kolla_bifrost_source_url: "https://git.openstack.org/openstack/bifrost"
 
-# Version (branch, tag, etc.) of Bifrost source code repository.
-kolla_bifrost_source_version: "master"
+# Version (branch, tag, etc.) of Bifrost source code repository. Default is
+# {{ openstack_branch }}.
+kolla_bifrost_source_version: "{{ openstack_branch }}"
 
 ###############################################################################
 # Diskimage-builder configuration.
diff --git a/ansible/group_vars/all/ipa b/ansible/group_vars/all/ipa
index 7a473e39c..e055710d7 100644
--- a/ansible/group_vars/all/ipa
+++ b/ansible/group_vars/all/ipa
@@ -10,8 +10,8 @@ ipa_build_images: False
 # URL of IPA source repository.
 ipa_build_source_url: "https://git.openstack.org/openstack/ironic-python-agent"
 
-# Version of IPA source repository.
-ipa_build_source_version: "master"
+# Version of IPA source repository. Default is {{ openstack_branch }}.
+ipa_build_source_version: "{{ openstack_branch }}"
 
 # URL of IPA upper constraints file.
 ipa_build_upper_constraints_file_url:
@@ -59,11 +59,16 @@ ipa_build_dib_git_elements: []
 ###############################################################################
 # Ironic Python Agent (IPA) images configuration.
 
+# Suffix of upstream Ironic deployment image files. Default is based on
+# {{ openstack_branch }}.
+ipa_images_upstream_url_suffix: >-
+  {% if openstack_branch != 'master' %}-{{ openstack_branch | replace('/', '-') }}{% endif %}
+
 # Name of Ironic deployment kernel image to register in Glance.
 ipa_images_kernel_name: "ipa.vmlinuz"
 
 # URL of Ironic deployment kernel image to download.
-ipa_kernel_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/coreos/files/coreos_production_pxe.vmlinuz"
+ipa_kernel_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/coreos/files/coreos_production_pxe{{ ipa_images_upstream_url_suffix }}.vmlinuz"
 
 # URL of checksum of Ironic deployment kernel image.
 ipa_kernel_checksum_url: "{{ ipa_kernel_upstream_url }}.{{ ipa_kernel_checksum_algorithm }}"
@@ -75,7 +80,7 @@ ipa_kernel_checksum_algorithm: "sha256"
 ipa_images_ramdisk_name: "ipa.initramfs"
 
 # URL of Ironic deployment ramdisk image to download.
-ipa_ramdisk_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/coreos/files/coreos_production_pxe_image-oem.cpio.gz"
+ipa_ramdisk_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/coreos/files/coreos_production_pxe_image-oem{{ ipa_images_upstream_url_suffix }}.cpio.gz"
 
 # URL of checksum of Ironic deployment ramdisk image.
 ipa_ramdisk_checksum_url: "{{ ipa_ramdisk_upstream_url }}.{{ ipa_ramdisk_checksum_algorithm }}"
diff --git a/ansible/group_vars/all/kolla b/ansible/group_vars/all/kolla
index 0604593c8..9809b5366 100644
--- a/ansible/group_vars/all/kolla
+++ b/ansible/group_vars/all/kolla
@@ -12,8 +12,8 @@ kolla_source_path: "{{ source_checkout_path ~ '/kolla' }}"
 kolla_source_url: "https://git.openstack.org/openstack/kolla"
 
 # Version (branch, tag, etc.) of Kolla source code repository if type is
-# 'source'.
-kolla_source_version: "master"
+# 'source'. Default is {{ openstack_branch }}.
+kolla_source_version: "{{ openstack_branch }}"
 
 # Path to virtualenv in which to install kolla.
 kolla_venv: "{{ virtualenv_path ~ '/kolla' }}"
@@ -34,8 +34,8 @@ kolla_ansible_source_path: "{{ lookup('env', 'KOLLA_SOURCE_PATH') | default(look
 kolla_ansible_source_url: "https://git.openstack.org/openstack/kolla-ansible"
 
 # Version (branch, tag, etc.) of Kolla Ansible source code repository if type
-# is 'source'.
-kolla_ansible_source_version: "master"
+# is 'source'. Default is {{ openstack_branch }}.
+kolla_ansible_source_version: "{{ openstack_branch }}"
 
 # Path to virtualenv in which to install kolla-ansible.
 kolla_ansible_venv: "{{ lookup('env', 'KOLLA_VENV_PATH') | default(lookup('env', 'PWD') ~ '/venvs/kolla-ansible', true) }}"
@@ -71,7 +71,8 @@ kolla_docker_registry_username:
 kolla_docker_registry_password:
 
 # Kolla OpenStack release version. This should be a Docker image tag.
-kolla_openstack_release: "master"
+# Default is {{ openstack_release }}.
+kolla_openstack_release: "{{ openstack_release }}"
 
 # Dict mapping names of sources to their definitions for
 # kolla_install_type=source. See kolla.common.config for details.
@@ -313,7 +314,7 @@ kolla_enable_tls_external: "no"
 kolla_openstack_logging_debug: "False"
 
 # Upper constraints file for installation of Kolla.
-kolla_upper_constraints_file: "https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt"
+kolla_upper_constraints_file: "https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt?h={{ openstack_branch }}"
 
 # User account to use for Kolla SSH access.
 kolla_ansible_user: kolla
diff --git a/ansible/group_vars/all/openstack b/ansible/group_vars/all/openstack
index ac0d4870a..e1d61ecef 100644
--- a/ansible/group_vars/all/openstack
+++ b/ansible/group_vars/all/openstack
@@ -1,4 +1,14 @@
 ---
+###############################################################################
+# OpenStack release configuration.
+
+# Name of the current OpenStack release. Default is "master".
+openstack_release: "master"
+
+# Name of the current OpenStack branch. Default is "master".
+openstack_branch: >-
+  {% if openstack_release != 'master' %}stable/{% endif %}{{ openstack_release | lower }}
+
 ###############################################################################
 # OpenStack authentication configuration.
 
diff --git a/etc/kayobe/bifrost.yml b/etc/kayobe/bifrost.yml
index 271ebdc89..078a6ced6 100644
--- a/etc/kayobe/bifrost.yml
+++ b/etc/kayobe/bifrost.yml
@@ -7,7 +7,8 @@
 # URL of Bifrost source code repository.
 #kolla_bifrost_source_url:
 
-# Version (branch, tag, etc.) of Bifrost source code repository.
+# Version (branch, tag, etc.) of Bifrost source code repository. Default is
+# {{ openstack_branch }}.
 #kolla_bifrost_source_version:
 
 ###############################################################################
diff --git a/etc/kayobe/ipa.yml b/etc/kayobe/ipa.yml
index 828a8ab34..63b0499d2 100644
--- a/etc/kayobe/ipa.yml
+++ b/etc/kayobe/ipa.yml
@@ -10,7 +10,7 @@
 # URL of IPA source repository.
 #ipa_build_source_url:
 
-# Version of IPA source repository.
+# Version of IPA source repository. Default is {{ openstack_branch }}.
 #ipa_build_source_version:
 
 # URL of IPA upper constraints file.
@@ -50,6 +50,10 @@
 ###############################################################################
 # Ironic Python Agent (IPA) images configuration.
 
+# Suffix of upstream Ironic deployment image files. Default is based on
+# {{ openstack_branch }}.
+#ipa_images_upstream_url_suffix:
+
 # Name of Ironic deployment kernel image to register in Glance.
 #ipa_images_kernel_name:
 
diff --git a/etc/kayobe/kolla.yml b/etc/kayobe/kolla.yml
index 42eef890b..aa3f4ffe2 100644
--- a/etc/kayobe/kolla.yml
+++ b/etc/kayobe/kolla.yml
@@ -14,7 +14,7 @@
 #kolla_source_url:
 
 # Version (branch, tag, etc.) of Kolla source code repository if type is
-# 'source'.
+# 'source'. Default is {{ openstack_branch }}.
 #kolla_source_version:
 
 # Path to virtualenv in which to install kolla.
@@ -36,7 +36,7 @@
 #kolla_ansible_source_url:
 
 # Version (branch, tag, etc.) of Kolla Ansible source code repository if type
-# is 'source'.
+# is 'source'. Default is {{ openstack_branch }}.
 #kolla_ansible_source_version:
 
 # Path to virtualenv in which to install kolla-ansible.
@@ -73,6 +73,7 @@
 #kolla_docker_registry_password:
 
 # Kolla OpenStack release version. This should be a Docker image tag.
+# Default is {{ openstack_release }}.
 #kolla_openstack_release:
 
 # Dict mapping names of sources to their definitions for
diff --git a/etc/kayobe/openstack.yml b/etc/kayobe/openstack.yml
new file mode 100644
index 000000000..1acfd0756
--- /dev/null
+++ b/etc/kayobe/openstack.yml
@@ -0,0 +1,13 @@
+---
+###############################################################################
+# OpenStack release configuration.
+
+# Name of the current OpenStack release. Default is "master".
+#openstack_release:
+
+# Name of the current OpenStack branch. Default is "master".
+#openstack_branch:
+
+###############################################################################
+# Dummy variable to allow Ansible to accept this file.
+workaround_ansible_issue_8743: yes
diff --git a/releasenotes/notes/openstack-branch-87df0c2f647037c0.yaml b/releasenotes/notes/openstack-branch-87df0c2f647037c0.yaml
new file mode 100644
index 000000000..eb5774f89
--- /dev/null
+++ b/releasenotes/notes/openstack-branch-87df0c2f647037c0.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Adds two new variables, ``openstack_release`` and ``openstack_branch``, in
+    ``${KAYOBE_CONFIG_PATH}/openstack.yml`` for setting the current OpenStack
+    release and branch in a single place.
diff --git a/tox.ini b/tox.ini
index 043d2533f..affaef9fd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -59,11 +59,8 @@ commands =
 [testenv:molecule]
 # Molecule only supports python 2.7 and 3.6.
 basepython = python2
-# Use stable/rocky upper-constraints for molecule since pytest 3.10 fails with
-# the following error:
-# AttributeError: 'Config' object has no attribute 'cache'
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt?h=stable/rocky}
+    -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
     -r{toxinidir}/test-requirements.txt
     -r{toxinidir}/doc/requirements.txt
 whitelist_externals =