https://ef.gy/hardening-ssh#SSH%20certificates
https://c-tek.tumblr.com/post/129804599384/did-ansible-just-hack-me?is_related_post=1
https://www.joyent.com/blog/automatic-dns-updates-with-containerbuddy
https://blather.michaelwlucas.com/archives/1106
https://awesome-docker.netlify.com/
http://www.tldp.org/HOWTO/ppp-ssh/
https://medium.com/@tech_phil/running-ansible-inside-docker-550d3bb2bdff
https://uisapp2.iu.edu/confluence-prd/pages/viewpage.action?pageId=280461906
http://dustwell.com/how-x-over-ssh-really-works.html
https://www.cyberciti.biz/tips/bash-shell-parameter-substitution-2.html