I have shell script with bunch of common functions to simplify particular tasks and then main script that when ran installs all needed packages, creates / copies various config files, pulls my C++ code from repo and builds my servers and installs those as daemons. It also installs cron jobs that execute backups / replication. It is smart enough to skip already performed steps and can safely run multiple times. It can run on Debian, Ubuntu, Arch and Mint.

It is fast and reliable and can deploy new infra and or restore state of that from backup. I use it for years without any problems.