diskimage-builder/roles/dib-ensure-debootstrap/tasks/main.yaml

- name: Install debootstrap/unstable
  # This is shell because doing it with native ansible modules went nowhere
  become: yes
  shell: |
    set -ex
    echo "APT::Default-Release: 'stable';" > /etc/apt/apt.conf.d/default-release
    echo "deb http://deb.debian.org/debian unstable main" > /etc/apt/sources.list.d/unstable-debian.list
    apt-get update
    apt-get install -y debootstrap/unstable
    # Remove the use of unstable as it seems to interfere with other tasks
    rm /etc/apt/sources.list.d/unstable-debian.list
    apt-get update