restart

September 2018 Update: Ansible 2.7 (to be released around October 2018) will include a new reboot module, which makes reboots a heck of a lot simpler (whether managing Windows, Mac, or Linux!):

- name: Reboot the server and wait for it to come back up.
  reboot:

That's it! Much easier than the older technique I used in Ansible < 2.7!

One pattern I often need to implement in my Ansible playbooks is "configure-reboot-configure", where you change some setting that requires a reboot to take effect, and you have to wait for the reboot to take place before continuing on with the rest of the playbook run.

For example, on my Raspberry Pi Dramble project, before installing Docker and Kubernetes, I need to make sure the Raspberry Pi's /boot/cmdline.txt file contains a couple cgroup features so Kubernetes runs correctly. But after adding these options, I also have to reboot the Pi.