Ansible task for Debian/Ubuntu that updates package cache, then as necessary: upgrades, reboots, wait for server to come back up to continue.

update-upgrade-reboot-wait.yml

# Upgrade Debian/Ubuntu based systems and reboot if necessary.
---
- name: "Update apt-get cache"
  apt:
    update_cache: yes

- name: "Check if there are packages available to be installed/upgraded"
  command: /usr/lib/update-notifier/apt-check --package-names
  register: packages

- name: "Upgrade all packages to the latest version"
  apt:
    upgrade: dist
  when: packages.stderr != ""

- name: "Check if a reboot is required"
  register: rebootfile
  stat: path=/var/run/reboot-required get_md5=no

- name: "Rebooting server if needed"
  shell: sleep 2 && shutdown -r now "Ansible reboot"
  async: 1
  poll: 0
  ignore_errors: true
  when: rebootfile.stat.exists == true

- name: "Waiting for server to come back after reboot"
  local_action: wait_for
  args:
    host: "{{ inventory_hostname }}"
    port: 22
    state: started
    delay: 20
    timeout: 120
  become: false
  when: rebootfile.stat.exists == true