Finally I hardcoded in the file  /etc/ansible/roles/os_nova/tasks/nova_install.yml

----
- name: Install the python venv
  import_role:
    name: "python_venv_build"
  vars:
    venv_python_executable: "{{ nova_venv_python_executable }}"
    venv_build_constraints: "{{ nova_git_constraints }}"
    venv_build_distro_package_list: "{{ nova_devel_distro_packages }}"
    venv_install_destination_path: "{{ nova_bin | dirname }}"
    venv_pip_install_args: "{{ nova_pip_install_args }}"
    venv_packages_to_symlink: >-
      {{ (nova_services['nova-compute']['group'] in group_names and nova_virt_type != 'ironic') | ternary(nova_compute_kvm_packages_to_symlink, []) }}
    venv_pip_packages: "{{ nova_venv_packages }}"
    venv_facts_when_changed:
      - section: "nova"
        option: "need_service_restart"
        value: "True"
      - section: "nova"
        option: "need_online_data_migrations"
        value: "False"
      - section: "nova"
        option: "venv_tag"
        value: "{{ nova_venv_tag }}"
  when: nova_install_method == 'source'

- name: Record local facts for distro path
  when: nova_install_method == 'distro'
  block:
    - name: Record the osa version deployed
      ini_file:
        dest: "/etc/ansible/facts.d/openstack_ansible.fact"
        section: nova
        option: venv_tag
        value: "{{ nova_venv_tag }}"
        mode: "0644"

    - name: Initialise the upgrade facts
      ini_file:
        dest: "/etc/ansible/facts.d/openstack_ansible.fact"
        section: nova
        option: "{{ item.name }}"
        value: "{{ item.state }}"
        mode: "0644"
      with_items:
        - name: "need_service_restart"
          state: "True"
        - name: "need_online_data_migrations"
          state: "False"
      when:
        - (install_packages is changed) or
          (ansible_local is not defined) or
          ('openstack_ansible' not in ansible_local) or
          ('nova' not in ansible_local['openstack_ansible']) or
          ('need_online_data_migrations' not in ansible_local['openstack_ansible']['nova']) or
          ('need_service_restart' not in ansible_local['openstack_ansible']['nova'])
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how to override it without hardcoding it ?