---
# Install HTTPS support for APT
- name: Install apt-transport-https
  apt:
    update_cache: true
    name:
      - apt-transport-https
      - gpg
      - dirmngr
    state: present
  register: apt_result
  retries: 3
  until: apt_result is succeeded

# Add the key
- name: Configure the apt key
  apt_key:
    keyserver: keyserver.ubuntu.com
    id: 06E85760C0A52C50
    state: present
  register: apt_key_result
  retries: 3
  until: apt_key_result is succeeded
  loop:

# Add the repository into source list
- name: Configure unifi repository
  apt_repository:
    repo: "{{ item }}"
    state: present
  loop:
    - deb http://www.ui.com/downloads/unifi/debian stable ubiquiti

- name: Install unifi
  apt:
    update_cache: true
    name: unifi
    state: present
  register: apt_result
  retries: 3
  until: apt_result is succeeded
...