install_method=distro and horizon_customization_module set in variables results into a broken horizon. Playbooks execute without errors.
Underlying cause is that "python-path={{ horizon_lib_dir | dirname }}/site-packages" is declared in apache config template, which expands into "/usr/share/site-packages" for a distro install. This directory does not exist, which leads to "ModuleNotFoundError: No module named 'horizon_customization'" for apache inside horizon container.
Overrides file is correctly copied to /usr/share/openstack-dashboard/horizon_customization/__init__.py, so this can be manually fixed by issuing "ln -s /usr/share/openstack-dashboard /usr/share/site-packages" inside the horizon container and restarting apache service, but this is an ugly solution.
This was tested with stable/wallaby branch, but I believe master is affected too since it has the same config and path variables. System packages do not matter either - this is broken with both system packages(Openstack Ussuri) and with updated apt repos(Openstack Wallaby).
Steps to reproduce:
Ubuntu 20.04 LTS
sudo apt update
sudo apt dist-upgrade
sudo reboot
sudo su
git clone https://opendev.org/openstack/openstack-ansible /opt/openstack-ansible
cd /opt/openstack-ansible
git checkout stable/wallaby
scripts/bootstrap-ansible.sh
export BOOTSTRAP_OPTS="bootstrap_host_install_method=distro"
scripts/bootstrap-aio.sh
touch /opt/overrides.py
echo "horizon_customization_module: /opt/overrides.py" >> /etc/openstack_deploy/user_variables.yml
cd /opt/openstack-ansible/playbooks
openstack-ansible setup-everything.yml
Playbooks will execute without errors but trying to open dashboard will result in 503 error.
Fix proposed to branch: master
Review: https:/