Ansible tasks to reboot hosts and wait for them to come back. Originally from https://support.ansible.com/hc/en-us/articles/201958037-Reboot-a-server-and-wait-for-it-to-come-back, but this article is no longer available. See also https://sethosii.github.io/2017/04/29/ansbile-reboot.html.

reboot.yaml

- name: "reboot hosts"
  shell: "sleep 2 && shutdown -r now 'Reboot triggered by Ansible'" # sleep 2 is needed, else this task might fail
  async: "1" # run asynchronously
  poll: "0" # don't ask for the status of the command, just fire and forget
  ignore_errors: yes # this command will get cut off by the reboot, so ignore errors
- name: "wait for hosts to come up again"
  wait_for:
    host: "{{ inventory_hostname }}"
    port: "22" # wait for ssh as this is what is needed for ansible
    state: "started"
    delay: "120" # start checking after this amount of time
    timeout: "360" # give up after this amount of time
  delegate_to: "localhost" # check from the machine executing the playbook