Keeping it simple is good advice, but that's not shell scripts once you have more than ~10 boxes. Picking a good config management and deployment tool, getting

Keeping it simple is good advice, but that's not shell scripts once you have more than ~10 boxes. Picking a good config management and deployment tool, getting everything checked into git, and being disciplined about how you do things will save you mountains of time in the long run. I'm currently on saltstack and it's a nice system; it eliminates a lot of the slowness I experienced with Ansible while conceptually working similarly (playbooks -> states, templates, inventory -> pillar, roles, etc). Everything is committed in git; sensitive data like keys are encrypted with a secret not in the repo using nacl. When I deploy, I know every machine is in exactly the same state running the same software and packages -- that is much much harder with ssh and shell scripts.