modify-sources.list.yml

---
- name: Backup Original Sources.list and Replace it with custom Sources.list File that points to local repository.
  hosts: all
  become: yes
  become_method: sudo
  tasks:
    - name: check if backup already exists
      stat:
         path: /etc/apt/sources.list_backup
      register: sources_backup
    
    - name: check if backup already exists
      stat:
         path: /etc/apt/sources.list
      register: sources_original

    - name: Backup Source.list only if it doesn't already exist.
      copy: 
          remote_src: true
          mode: preserve
          src: /etc/apt/sources.list
          dest: /etc/apt/sources.list_backup
      when: 
        - sources_backup.stat.exists == False
    
    - name: Delete the original if Backup and Original Exists
      file:
         path: /etc/apt/sources.list
         state: absent
      when:
        - sources_original.stat.exists
        - sources_backup.stat.exists

    - name: Source.list Bionic
      copy:
         dest: /etc/apt/sources.list
         content: |
            deb ftp://192.168.4.242/ubuntu_repo bionic main restricted universe multiverse
            deb ftp://192.168.4.242/ubuntu_repo bionic-security main restricted universe multiverse
            deb ftp://192.168.4.242/ubuntu_repo bionic-updates main restricted universe multiverse
            deb ftp://192.168.4.242/ubuntu_repo bionic-backports main restricted universe multiverse
      when: ansible_lsb.codename == 'bionic'

    - name: Source.list Xenial 
      copy:
         dest: /etc/apt/sources.list
         content: |
           deb ftp://192.168.4.242/ubuntu_repo xenial main restricted universe multiverse
           deb ftp://192.168.4.242/ubuntu_repo xenial-security main restricted universe multiverse
           deb ftp://192.168.4.242/ubuntu_repo xenial-updates main restricted universe multiverse
           deb ftp://192.168.4.242/ubuntu_repo xenial-backports main restricted universe multiverse
      when: ansible_lsb.codename == 'xenial'